Reference
Perfumery carries a working vocabulary borrowed from chemistry, from the French tradition and from the bench itself. These are the 102 terms you are most likely to meet on a supplier’s label, in a formula, or in someone else’s description of a material — defined plainly, without circling back on themselves.
Also called absolue
A highly concentrated aromatic extract obtained by washing a concrete with ethanol, chilling the mixture to precipitate waxes, filtering them off and removing the alcohol. Absolutes are usually richer and truer to the living flower than the corresponding essential oil, and are the standard form for jasmine, tuberose and mimosa, which do not survive steam distillation.
See also Concrete · Solvent Extraction · Essential Oil 12 materials →
Also called chord
A deliberate blend of two or more materials that reads as a single new smell rather than as its parts. A good accord is the basic unit of construction in perfumery: the classic fougère accord of lavender, coumarin and oakmoss is heard as one idea, not three ingredients.
A chemical family carrying the –CHO group, and one of the most important classes in perfumery. The fatty aldehydes (C10, C11, C12) give the soapy, waxy, candle-like sparkle associated with the aldehydic florals; others such as benzaldehyde smell of bitter almond and vanillin belongs here too. Most are extremely powerful and are normally used well under one percent.
See also Impact · Dilution · Overdose 8 materials →
Also called declarable allergens, 26 allergens
A substance capable of provoking an allergic response in susceptible people. EU cosmetic law requires a defined list of fragrance allergens — long-standing materials such as linalool, limonene, citronellol, eugenol and geraniol among them — to be named on the label once they exceed set thresholds in the finished product. Their presence is normal and not a sign of poor quality.
See also IFRA · Sensitiser · Safety Data Sheet
Also called ambery, amber accord
A warm, sweet, resinous accord — classically labdanum with vanillin and benzoin — and one of the most persistent confusions in perfumery vocabulary. Amber in this sense has nothing to do with ambergris, and nothing to do with fossilised tree resin, which is odourless. It is a constructed effect, not a material.
See also Ambergris · Accord · Resinoid · Balsam 26 materials →
Also called ambra, grey amber
A substance formed in the digestive tract of the sperm whale and aged by years at sea, giving a salty, marine, animalic and radiant material of legendary fixative power. Genuine ambergris is scarce, expensive and legally restricted in some markets, so modern formulas use synthetics such as Ambroxan and Cetalox instead.
See also Amber · Fixative · Reconstitution · Tincture 1 material →
Also called specific anosmia, smell blindness
The inability to perceive a smell. General anosmia is the total loss of the sense; far more relevant to perfumers is specific anosmia, an inherited blind spot for one material while the rest of the sense works normally. Musks are the notorious case — a significant minority of people cannot smell certain macrocyclic or polycyclic musks at all, which is one reason formulas are built with several musks rather than one.
See also Musk · Odour Threshold · Olfactory Fatigue
Also called aromachemical, aroma molecule
A single odorous compound used as a perfumery ingredient, whether synthesised in a plant or isolated from a natural material. The term describes purity of composition, not origin: geraniol isolated from palmarosa and geraniol made synthetically are the same molecule and smell the same.
See also Isolate · Synthetic · Natural 2 materials →
Also called ittar, ruh
A traditional South Asian and Middle Eastern extract in which botanicals are hydro-distilled directly into a receiving vessel of sandalwood oil, which captures the aroma as it comes over. The sandalwood is part of the finished material rather than a dilution of it. Ruh gulab and mitti attar are well-known examples.
See also Distillation · Essential Oil
A resinous exudate from a tree or shrub, typically thick, sweet and vanillic or cinnamic in character. Peru balsam, tolu balsam and styrax are the standard perfumery examples. Balsams are usually processed into resinoids before use because the crude material is too viscous and too full of non-odorous matter to work with directly.
See also Resinoid · Oleoresin · Fixative 12 materials →
Also called speciality base, specialty base
A pre-composed blend supplied as a single ingredient. Bases exist for two reasons: to reproduce a material that cannot be sourced or used (a restricted natural, an animal note), and to supply a complex effect — a full peach, a rounded amber — as one line in a formula. Note that this sense is unrelated to a base note.
See also Accord · Base Note · Reconstitution 20 materials →
Also called basenote, bottom note, fond
The least volatile part of a composition, appearing late and persisting longest — commonly woods, resins, musks and animalic materials. Base notes give a fragrance its weight and its ending, and often continue on skin long after the top and heart have gone.
See also Top Note · Heart Note · Substantivity · Volatility
Also called lot number
The manufacturer's identifier for a specific production run, printed on the label and referenced on the certificate of analysis. Naturals in particular vary between batches, so recording the batch number alongside a formula is the only way to explain why a blend you loved last year smells different when you rebuild it.
See also Certificate of Analysis · Natural
Also called BB
A near-odourless, high-boiling solvent used to dilute perfumery materials and as a mild fixative. It is heavier and less volatile than DPG, dissolves resins and crystalline solids that DPG struggles with, and slows the evaporation of what it carries.
See also Solvent · Dipropylene Glycol · Fixative
Also called scent strip, smelling strip, mouillette, touche
A strip of absorbent, odour-free paper dipped into a material or blend for evaluation. The blotter is the perfumer's basic instrument: it presents a consistent surface, can be labelled and dated, and lets you follow a dry-down over hours or days without committing anything to skin.
See also Dry-down · Evaluation 2 materials →
Also called CAS RN, CAS registry number
A unique numeric identifier assigned to a chemical substance by the Chemical Abstracts Service, written as three hyphenated groups such as 78-70-6 for linalool. Because trade names vary wildly between suppliers, the CAS number is the reliable way to confirm that two products are in fact the same material.
See also Synonym · Certificate of Analysis
Also called COA, C of A
A document issued with a specific batch stating what was measured and what the results were — typically appearance, purity or assay, refractive index, specific gravity and optical rotation, sometimes with a chromatographic profile. It describes that batch only, which is exactly what makes it useful.
See also Batch Number · Purity · Specific Gravity · Refractive Index
The overall identity of a smell — what it is, described as a whole, before you begin picking it apart into facets. Two materials can share every facet on a list and still have quite different character, which is why evaluation notes record an impression as well as an inventory.
See also Facet · Evaluation · Note
Also called chypré
A fragrance family built on the contrast between bright citrus at the top and a mossy, woody, labdanum base, named after François Coty's Chypre of 1917. Reformulation of oakmoss under IFRA restrictions has forced the modern chypre to be rebuilt with substitutes, which is why contemporary examples smell notably different from vintage ones.
See also Fougère · Accord · IFRA · Base Note 2 materials →
Also called supercritical extract, SCFE, select extract, total extract
An extract produced using carbon dioxide held above its critical point, where it behaves as both liquid and gas and acts as a tunable solvent. The process runs cool and leaves no residue, so results are often strikingly true to the raw botanical. Select extracts approximate an essential oil profile; total extracts pull waxes and pigments as well and are frequently semi-solid.
See also Solvent Extraction · Essential Oil · Absolute 1 material →
Also called compound, mixing
The act of physically weighing out and combining the materials of a formula. Compounding is a bench discipline rather than a creative one: the same formula compounded carelessly and carefully produces two different smells.
Also called strength, eau de parfum, EDP, EDT, extrait
The proportion of fragrance compound dissolved in the finished alcoholic product. The familiar names describe broad and unregulated ranges rather than fixed figures — extrait sits highest, then eau de parfum, eau de toilette and eau de cologne. Concentration governs intensity and longevity, but not quality: a well-built eau de toilette will outperform a badly built extrait.
See also Dilution · Fragrance Compound
The waxy, semi-solid first product of solvent extraction from fresh plant material, containing the aromatic compounds together with plant waxes and pigments. Concretes are used directly in some soap and candle work, but in fine fragrance they are normally processed onward into an absolute.
See also Absolute · Solvent Extraction
A crystalline material with a sweet, hay-like, tonka and new-mown-grass character, first isolated from tonka bean and among the earliest aroma chemicals used in modern perfumery. Its introduction into Fougère Royale in 1882 effectively founded the fougère family.
See also Accord · Fixative 3 materials →
Also called radiance, projection
How readily a smell travels away from its source into the surrounding air. Diffusion is not the same as strength — a material can be intense up close yet sit tight against the skin, while another reads as light but fills a room. Aldehydes and many citrus and green materials are prized for diffusion.
See also Sillage · Impact · Volatility
A material dissolved in a solvent at a known percentage, and the standard way to work with perfumery ingredients. Dilution makes powerful materials weighable, makes them smellable as themselves rather than as an assault, and makes small quantities practical to handle. Working strengths of 10% and 1% are the everyday cases.
See also Serial Dilution · Solvent · Working Strength
Also called DPG
The most widely used diluent in perfumery: near-odourless, low in volatility, safe on skin and miscible with most aroma chemicals. DPG is the default choice for making up dilutions for evaluation, though it will not dissolve every resin or crystalline solid.
See also Solvent · Benzyl Benzoate · Triethyl Citrate · Dilution 1 material →
Also called steam distillation, hydrodistillation
The separation of volatile aromatic compounds from plant material using steam or boiling water, followed by condensation and separation of oil from water. It is the principal route to essential oils, and it inevitably alters the smell: heat drives some compounds off and creates others, which is why distilled rose and rose absolute are quite different things.
See also Essential Oil · Hydrosol · Fractionation · Rectification
Also called drydown, dry out
The evolution of a material or composition over time as its more volatile components leave, and the final residual character that remains. Evaluating a material means following its dry-down at intervals over hours and days, not judging the first impression from the bottle.
See also Blotter · Base Note · Substantivity · Volatility
A historical extraction method in which fresh petals are laid on trays of purified cold fat, which absorbs their scent over repeated changes of flowers. The resulting scented fat, or pomade, is then washed with alcohol to yield an absolute. Enfleurage is effectively obsolete commercially, but survives as a craft practice for delicate flowers such as tuberose and jasmine.
See also Pomade · Absolute · Solvent Extraction
Also called EO, volatile oil, ethereal oil
The volatile aromatic fraction of a botanical, obtained by distillation or, for citrus peel, by expression. Essential oils are complex mixtures of dozens to hundreds of compounds whose proportions shift with origin, season, harvest and processing — which is why two lots of the same oil rarely smell identical.
See also Distillation · Expression · Natural · Absolute 21 materials →
A large chemical family formed from an acid and an alcohol, and the backbone of fruity and many floral effects. Ethyl acetate, benzyl acetate and linalyl acetate are typical: mostly bright, sweet and fruity, generally volatile, and prone to slow hydrolysis in the presence of water and acid.
See also Top Note · Volatility 7 materials →
Also called olfactory evaluation, smelling
The disciplined practice of smelling a material or blend and recording what it does — character, strength, facets, behaviour over time. Evaluation is what converts smelling into knowledge, and it depends on doing the same thing every time: same dilution, same blotter, same intervals, written down.
See also Blotter · Dry-down · Olfactory Fatigue · Working Strength
Also called cold pressing, scarification
The mechanical extraction of oil from citrus peel by pressing or abrasion, without heat. Expressed citrus oils are fresher and more true than distilled ones, but they carry non-volatile compounds including furocoumarins, which makes phototoxicity a real consideration.
See also Phototoxicity · Essential Oil · Distillation 29 materials →
Also called nuance
A distinguishable aspect within a single smell. Patchouli, for instance, carries earthy, camphoraceous, woody and sweet-winey facets at once; naming them is how a perfumer learns to select the right material for the effect actually wanted.
See also Evaluation · Character
A material that extends the life of a composition on skin or blotter, either by being tenacious itself or by physically slowing the evaporation of lighter components. Musks, resins, balsams and heavy woods act as fixatives; so, less obviously, do high-boiling solvents such as benzyl benzoate.
See also Substantivity · Base Note · Musk · Resinoid 2 materials →
The lowest temperature at which a liquid gives off enough vapour to ignite in air. It appears on every safety data sheet and governs how a material may be shipped and stored — low flash point materials such as ethanol and many citrus oils attract transport restrictions.
See also Safety Data Sheet
Also called recipe, compound formula
The written specification of a composition: every material, its dilution, and its quantity by weight. Formulas are conventionally written in parts adding to 1000, which makes them scalable to any batch size and independent of the units used at the bench.
See also Parts Per Thousand · Compounding · Weighing
Also called fougere, fern
A fragrance family founded by Houbigant's Fougère Royale in 1882 and built on lavender, coumarin and oakmoss. The name means fern, though ferns have no smell — it describes an imagined idea of green woodland rather than any botanical reality. The family underpins a very large share of masculine fragrance.
See also Chypre · Coumarin · Accord 6 materials →
Also called fractional distillation
Redistilling an oil to separate it into fractions by boiling point, either to remove an unwanted portion or to isolate a desirable one. Terpeneless citrus oils are made this way, as are the individual fractions of ylang-ylang.
See also Terpeneless · Rectification · Isolate
Also called concentrate, juice, compound
The finished blend of aromatic materials before it is diluted into alcohol or added to a product base. This is what a perfumer actually composes; the eau de parfum on the shelf is the compound at some percentage in alcohol and water.
See also Concentration · Formula
Also called furanocoumarin, bergapten
A class of non-volatile compounds present in expressed citrus oils, notably bergamot, and the cause of their phototoxicity. Bergapten-free or FCF grades have been treated to remove them, which makes higher use levels possible at some cost in character.
See also Phototoxicity · Expression · IFRA
Also called gas chromatography, mass spectrometry, GC-MS
The analytical pairing used to separate a mixture into its components and identify them. GC/MS underpins quality control, adulteration detection and the reconstruction of naturals, and its output often accompanies a certificate of analysis for a natural material.
See also Certificate of Analysis · Purity · Reconstitution
A fragrance family built on edible effects — vanilla, caramel, chocolate, almond, sugar — generally dated to Thierry Mugler's Angel in 1992. Gourmands lean heavily on ethyl maltol, vanillin and the lactones, and tend to be sweet and highly substantive.
See also Lactone · Vanillin · Accord 6 materials →
A descriptive family covering the smell of cut stems, crushed leaves and unripe vegetation — sharp, cool and slightly bitter. Cis-3-hexenol is the reference point; galbanum supplies the same idea in a darker, more resinous register.
See also Facet · Top Note 25 materials →
Also called headspace analysis, living flower technique
A technique in which the air surrounding a living flower or object is captured and analysed, so that its smell can be characterised without extracting it. Headspace made it possible to build credible reconstitutions of flowers that yield nothing to distillation or solvent — lily of the valley, lilac, freesia.
See also Reconstitution · GC/MS
Also called middle note, mid note, corps
The central body of a composition, emerging as the top notes fade and lasting for a few hours. Florals and spices commonly live here. The heart carries the identity of most fragrances — it is what people mean when they describe what something smells like.
See also Top Note · Base Note · Volatility
Also called hydrolat, floral water, distillate water
The aqueous portion left after distillation, holding the small quantity of water-soluble aromatic compounds that did not separate into the oil. Rose and orange blossom waters are the well-known examples. Hydrosols are far weaker than oils and, being mostly water, are prone to microbial spoilage.
See also Distillation · Essential Oil
Also called International Fragrance Association, IFRA standards
The industry body that publishes the IFRA Standards — the restrictions, specifications and prohibitions governing the safe use of fragrance materials, revised in numbered amendments. Standards set maximum use levels by product category according to how the product contacts skin, so the permitted level in a fine fragrance differs from that in a body lotion.
See also Allergen · Safety Data Sheet · Sensitiser
Also called strength, tenacity of impression
How strongly a material asserts itself at a given concentration. High-impact materials — many aldehydes, thiols, pyrazines — are perceptible at vanishingly small percentages and will dominate a formula if treated as ordinary ingredients.
See also Odour Threshold · Overdose · Dilution
Also called alpha ionone, beta ionone, methyl ionone
A family of materials responsible for the violet and orris effect, with woody, powdery and fruity facets depending on the isomer. Alpha ionone leans floral and woody, beta ionone drier and more violet-leaf; the methyl ionones are softer and are the backbone of the classic powdery iris accord.
See also Accord · Facet 3 materials →
Also called natural isolate
A single compound separated out from a natural material, usually by fractional distillation. Eugenol from clove and citral from litsea are typical. An isolate is chemically identical to the synthetic version of the same molecule but can be described as naturally derived.
See also Aroma Chemical · Fractionation · Natural
Also called IPM
An odourless, oily diluent used where an alcohol-free or oil-soluble carrier is needed, particularly for oil-based and roll-on formats. It is light, spreads well on skin and does not sting, but it is not miscible with everything DPG handles.
See also Solvent · Dipropylene Glycol · Dilution 1 material →
A cyclic ester family giving creamy, milky, coconut and stone-fruit effects. Gamma-decalactone is the reference peach; gamma-nonalactone reads as coconut; the larger musk lactones cross into musk territory. Lactones are generally soft, sweet and persistent.
See also Ester · Musk 3 materials →
Also called cuir, leather accord
A constructed accord rather than an extract, since leather itself yields nothing to distillation. The effect is built from smoky, tarry and animalic materials — birch tar, isobutyl quinoline, safraleine, castoreum substitutes — and ranges from the dry suede of a soft leather to the harsh tar of a Russian leather.
See also Accord · Phenol · Base 9 materials →
Also called maturation, ageing
The resting period after compounding, during which a blend is left sealed and undisturbed so that its components integrate. Freshly mixed compositions frequently smell harsh or disjointed; several weeks of maceration commonly settles them. Judging a formula on the day it was made is a standard beginner's error.
See also Compounding · Shelf Life
Also called blender
A material added not for its own character but to adjust, connect or smooth the materials around it. Hedione is the classic modifier: on its own it is faint and unremarkable, yet it makes florals bloom and softens the joints of a composition.
Also called macrocyclic musk, polycyclic musk, nitro musk, white musk
A family of materials — now entirely synthetic in commercial practice — providing skin-like, warm, sometimes powdery or soapy effects with exceptional substantivity. Macrocyclic musks are the large-ring class and are generally considered the finest; polycyclic musks are cheaper and more diffusive; nitro musks are largely obsolete on safety grounds. Specific anosmia to individual musks is common.
See also Anosmia · Fixative · Base Note 14 materials →
Also called naturals, botanical
A material obtained from a plant or animal source by physical means such as distillation, expression or extraction, without chemical modification. Naturals are complex mixtures, variable by batch and origin, and often carry restrictions their individual components would not. Natural is a statement about origin, not about safety or quality.
See also Synthetic · Essential Oil · Batch Number 7 materials →
Also called undiluted, straight
A material used or smelled at full strength, undiluted. Smelling neat is informative for gentle woods and musks and actively misleading for powerful ones — many aroma chemicals smell harsh, flat or simply wrong neat, and only resolve into their true character at one percent or below.
See also Dilution · Working Strength · Thiol · Impact
A chemical family valued for stability rather than novelty. Nitriles frequently smell close to the corresponding aldehyde but resist discolouration and oxidation, which makes them useful in bleach, detergent and other aggressive bases where an aldehyde would not survive.
Used two ways, and worth keeping distinct. It can mean a single perceived smell within a composition ("a jasmine note"), or a position in the evaporation sequence — top, heart or base. The second sense describes volatility, not ingredients.
See also Top Note · Heart Note · Base Note · Facet
Also called detection threshold, odor threshold
The lowest concentration at which a material can be detected. Thresholds vary across an enormous range — some thiols are perceptible at parts per trillion while some woody materials need percent-level presence — and this, far more than any notion of intrinsic strength, determines how a material must be dosed.
A concentrated extract containing both the essential oil and the natural resins of a botanical, usually produced by solvent extraction from spices or resinous material. Pepper, ginger and vanilla oleoresins carry more of the whole raw material's character than the corresponding distilled oil.
See also Resinoid · Solvent Extraction · Balsam
Also called nose fatigue, adaptation, habituation
The rapid loss of sensitivity to a smell during continuous exposure. It is a normal feature of the sense, not a failing of the nose, and it is why evaluation is done in short sessions with breaks, and why a perfumer stops trusting judgement made an hour into concentrated smelling.
See also Evaluation · Anosmia
The angle by which a material rotates plane-polarised light, reported on certificates of analysis for many naturals. Because it reflects the balance of mirror-image molecules present, it is a sensitive indicator of authenticity — adulteration frequently shifts it outside the expected range.
See also Certificate of Analysis · Refractive Index
The deliberate use of a material far above its conventional level, as a compositional decision rather than an error. Overdoses are behind a number of landmark fragrances — the aldehydes of Chanel No. 5, the Iso E Super of Molecule 01 — and can turn a familiar material into the entire idea of a composition.
The reaction of a material with atmospheric oxygen, degrading its smell over time and, in some cases, increasing its capacity to sensitise skin. Citrus oils and terpene-rich naturals are especially vulnerable. Full, tightly closed, cool, dark storage is the practical defence.
See also Shelf Life · Terpene · Sensitiser
Also called ppt, parts per 1000, per mille
The conventional way of writing perfume formulas, with all quantities summing to 1000. Working in parts rather than absolute weights makes a formula scalable to any batch and keeps the proportions readable at a glance.
See also Formula · Weighing · Compounding
A chemical family carrying a hydroxyl group on an aromatic ring, generally smoky, medicinal, spicy or tarry. Eugenol gives clove, guaiacol reads smoky, and the cresols supply the animalic and leathery undertones found in narcissus and birch tar.
See also Facet 3 materials →
Also called photosensitivity, photosensitisation
A reaction in which a material on skin causes burning or pigmentation when exposed to sunlight. In perfumery it is chiefly associated with furocoumarins in expressed citrus oils, and it is the reason IFRA restricts expressed bergamot in leave-on products while bergapten-free grades are permitted at much higher levels.
See also Furocoumarin · Expression · IFRA
The scented fat produced by enfleurage, saturated with floral aroma after repeated changes of petals. It is an intermediate rather than a finished material, washed with alcohol to give an absolute.
See also Enfleurage · Absolute
Also called assay
The proportion of a product that is the named substance, stated on the certificate of analysis. Higher purity is not automatically better in perfumery: trace impurities sometimes contribute meaningfully to a material's character, and a 95% commercial grade may smell rounder than a 99.9% one.
See also Certificate of Analysis · GC/MS · Aroma Chemical
A nitrogen-containing family responsible for roasted, nutty, green-vegetal and earthy effects — coffee, cocoa, bell pepper, roasted hazelnut. Pyrazines are among the most powerful materials in common use, with some detectable in the parts-per-trillion range.
See also Odour Threshold · Impact
Also called reconstruction, RCO
A blend built to reproduce the smell of a natural material, using aroma chemicals and sometimes a proportion of the natural itself. Reconstitutions exist where the natural is unavailable, restricted, prohibitively expensive or impossible to extract — and they are how flowers such as lily of the valley are represented at all.
Redistilling a material to clean it up — removing colour, off-notes or unwanted fractions. Rectified oils are more consistent and better behaved in a formula, at the cost of some of the complexity that made the crude material interesting.
See also Fractionation · Distillation · Terpeneless
Also called RI
A measure of how much a material bends light passing through it, reported on certificates of analysis. Quick to measure and characteristic for a given material, it functions as a routine identity and quality check.
See also Certificate of Analysis · Specific Gravity · Optical Rotation
An extract prepared from dried resinous material — balsams, gums, exudates — using a hydrocarbon or alcohol solvent. Resinoids are viscous, deep and highly tenacious, and function as both odour and fixative. Benzoin, labdanum and myrrh resinoids are the standard examples.
See also Balsam · Oleoresin · Fixative 2 materials →
Also called SDS, MSDS
The standardised document accompanying a chemical product, covering hazards, handling, storage, first aid, physical properties and disposal in sixteen defined sections. It is a safety and compliance document rather than a perfumery one — it will tell you the flash point but not the smell.
See also Flash Point · IFRA · Certificate of Analysis
An ester family — benzyl, amyl and hexyl salicylate among them — giving soft, warm, slightly powdery floral effects with a suntan-lotion quality. Salicylates are quiet on their own but excellent volume-builders, and appear in large proportions in many floral compositions.
See also Ester · Modifier 1 material →
The condensation product of an aldehyde and an amine — most familiarly methyl anthranilate with an aldehyde such as hydroxycitronellal. Schiff bases are tenacious and smoother than their components, though they tend to discolour over time.
Also called sensitizer, skin sensitisation
A material capable of provoking an allergic response after repeated exposure, in contrast to an irritant, which acts on first contact. Sensitisation potential drives many IFRA restrictions, and oxidised materials frequently sensitise more strongly than fresh ones.
Making a weak dilution in stages from a stronger one rather than in a single step — 10% from neat, then 1% from the 10%. Weighing 0.1 g accurately is difficult; weighing 1 g of a 10% solution is not, so serial dilution converts a precision problem into an arithmetic one.
See also Dilution · Working Strength · Weighing
A fifteen-carbon terpene class, heavier and less volatile than the monoterpenes. Sesquiterpenes are common in woods, roots and resins — santalol in sandalwood, patchoulol in patchouli — and contribute substantivity as well as character.
See also Terpene · Base Note · Substantivity
How long a material remains fit to use. Citrus and other terpene-rich oils may decline within a year or two of opening; resins, absolutes and many aroma chemicals last for years, and a few naturals such as patchouli and sandalwood genuinely improve. Air in the bottle, warmth and light are the main enemies.
See also Oxidation · Maceration
Also called trail, wake
The scented trail a wearer leaves behind them, from the French for the wake of a boat. Sillage is a property of the finished fragrance in movement, distinct from projection at rest and from longevity, and it depends as much on diffusive materials as on sheer concentration.
See also Diffusion · Substantivity
Also called diluent, carrier
A liquid used to dissolve aromatic materials, whether for dilution at the bench or as the medium of the finished product. The choice matters: DPG, ethanol, IPM, TEC and benzyl benzoate differ in volatility, solubility range and skin behaviour, and a solvent that cannot dissolve your material is no solvent at all.
See also Dipropylene Glycol · Isopropyl Myristate · Triethyl Citrate · Benzyl Benzoate · Dilution 3 materials →
Washing plant material with a volatile hydrocarbon solvent, then evaporating the solvent to leave a concrete or resinoid. Because it runs cool, extraction preserves delicate compounds that distillation would destroy, which is why it is the route for jasmine, tuberose and other heat-sensitive flowers.
See also Concrete · Absolute · Resinoid · CO2 Extract
Also called SG, relative density
The density of a material relative to water, reported on certificates of analysis. It is a standard identity check, and it is also the reason perfumery works by weight rather than volume — materials of equal volume can differ substantially in mass.
See also Certificate of Analysis · Weighing · Refractive Index
Also called longevity, tenacity, lasting power
How long a material or composition remains perceptible on skin or blotter. Substantivity is governed largely by volatility and molecular weight, and it is independent of strength — a material can be quiet but last all day, or brilliant and gone in twenty minutes.
See also Volatility · Fixative · Base Note · Dry-down
An alternative name for the same material. Perfumery materials commonly carry a chemical name, several trade names and a number of informal ones, which is why catalogues list synonyms and why the CAS number is the safest identifier when ordering.
See also CAS Number · Aroma Chemical
Also called synthetics, man-made
A material produced by chemical synthesis rather than extracted from a natural source. Synthetics offer consistency, availability, defined purity and effects with no natural equivalent, and they make up the majority of most modern formulas. Nothing about the origin implies inferiority — many synthetics are safer and more reliable than the naturals they stand beside.
See also Aroma Chemical · Natural · Isolate
Also called monoterpene
A hydrocarbon class built from five-carbon isoprene units and abundant in essential oils. The monoterpenes — limonene, pinene, myrcene — are light, fresh and highly volatile, and they oxidise readily, which is the main reason citrus oils deteriorate.
See also Sesquiterpene · Terpeneless · Oxidation · Volatility
Also called folded oil, terpene-free
An oil from which the monoterpene hydrocarbons have been removed by fractionation, leaving a more concentrated, more stable and more soluble product. Terpeneless citrus oils resist oxidation far better than the whole oils, though the top-note lift is somewhat diminished.
See also Terpene · Fractionation · Oxidation
Also called mercaptan, sulphur note
A sulphur-containing family among the most powerful odorants known, detectable at parts per trillion. Repellent when neat, thiols supply the definitive character of grapefruit, blackcurrant, coffee and tropical fruits at extreme dilution — a case where the neat smell tells you almost nothing about the useful one.
See also Odour Threshold · Impact · Dilution
A material prepared by steeping raw matter — resin, vanilla pod, oakmoss, ambergris — in ethanol over weeks or months, then filtering. Tincturing is the classical way to bring solids and animalics into a form that will blend, and it is entirely practical at home.
See also Solvent · Maceration
Also called topnote, head note, tête
The most volatile part of a composition, giving the first impression and generally spent within fifteen minutes to an hour. Citrus, light green materials and small esters live here. Top notes sell a fragrance but describe it least.
See also Heart Note · Base Note · Volatility · Dry-down
Also called TEC
An odourless diluent and fixative, useful where DPG is unsuitable and valued in alcohol-free and cosmetic applications. It is mild on skin and readily biodegradable.
See also Solvent · Dipropylene Glycol · Fixative 1 material →
The principal odorous compound of vanilla, first synthesised in 1874 and among the most widely used materials in the world. It is a crystalline solid, sweet and warm, and it discolours anything it is put into over time — a well-known nuisance in pale products. Ethylvanillin is several times stronger and rather less true to the bean.
See also Amber · Gourmand · Fixative 2 materials →
The readiness with which a material evaporates, and the single property that determines whether it behaves as a top, heart or base note. Volatility tracks broadly with molecular weight and boiling point, and it governs the shape a composition takes over time.
See also Top Note · Heart Note · Base Note · Substantivity
Also called balance, scale, gravimetric
The measurement of materials by mass rather than volume, and the standard practice in perfumery. Drops vary with viscosity, temperature and pipette; grams do not. A balance reading to 0.001 g is the practical entry point for bench work with dilutions.
See also Formula · Parts Per Thousand · Serial Dilution · Specific Gravity 4 materials →
Also called evaluation dilution, standard dilution
The dilution at which a material is routinely smelled and used. Most aroma chemicals are evaluated at 10% or 1%, powerful materials considerably lower, and gentle woods and musks sometimes neat. Recording the working strength alongside every evaluation note is what makes those notes comparable later.
See also Dilution · Serial Dilution · Evaluation · Odour Threshold
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Study with a teacher
Knowing the vocabulary is not the same as knowing the craft. A glossary can tell you what substantivity means; it cannot tell you why your accord collapses after twenty minutes, or which of your four materials is causing it.
The Alurent Perfumery Online School teaches perfumery in proper sequence — materials, accord building, formulation and evaluation — with set exercises and a tutor responding to the work you actually make. If you have assembled your understanding from forums and scattered reading, it is the fastest way we know to turn that into real technique.
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