List of Primary Odors


Are There Primary Odors?

It is understood that human vision is typically based on three primary colors: red, green, and blue; that there are at least five primary tastes: bitter, sweet, sour, salty, and umami; that there are primary touch sensations: vibration, warm, cold, pressure, pleasure, and pain; finally, that hearing is based on a frequency scale with repeating octave units and harmonic content perceived as timbre. But what about smell? Are there primary odors like with vision, touch, and taste, or is smell encoded in more complexity like hearing?

The current consensus is that vertebrate olfaction is based on pattern recognition, that any given odorant excites its own distinctive pattern of olfactory neurons, and the exact pattern results in the recognition of an odor. Humans have around 400 receptor genes implicated in olfaction, although each individual human only expresses between about 200 and 350 of them, so each receptor is believed to participate strictly in pattern recognition without contributing any odor quality on its own. But the evidence from assays of olfactory receptor responses to odorants points strongly to at least some olfactory receptors being directly responsible for aroma notes, including soapy, musky, sulfurous, muguet, woody, minty, and muttony, to name just a few. And while odor recognition probably does involve all several hundred receptor classes holistically, odor perception is demonstrably a separate phenomenon - consider how citrus, herbal, and camphorous all share certain terpene-like qualia, or how bready, sugary, and muguet all share a certain rough spongy granularity.


So What Do We Call Them?

But there is an inherent linguistic problem in naming aroma notes that correlate to each receptor. Are existing descriptors numerous enough to be applied to hundreds of receptors and potentially almost as many perceptual notes? And even if they are, the words that are traditionally used to describe and name odors are most often based on what the odor smells like, in other words they describe whole patterns, so they would not be suitable to name individual parts of a pattern. Worse, different people disagree on what some of the words mean. I could hand you a flower while commenting that I think smells "waxy", referring to the fresh, smooth aspect of waxiness, whereas you might interpret "waxy" to mean an animalic-tallowy aspect or a sweet scented-candle aspect and therefore, after sniffing the same flower, reply "wow, not to me."


A Proposed System

So a system is hereby presented with which to name the aroma perceptual qualities (APQs) associated with each olfactory receptor, under the assumption that each olfactory receptor may potentially correspond directly to an APQ. If any do not, then the name generated by the system for that receptor would simply be meaningless on its own. Some APQs might be formed combinatorially, in which case more than one name would be hyphenated together to describe that APQ at the receptor level. For now, a self-consistent naming system can be constructed, and ultimately, when more information is available, the systematic names can be assigned as necessary. This system shall be called Nuanced Olfactory Syllable Encoded System or NOSES.


Syllables for Families

To start off, a series of core syllables is proposed for the families of olfactory receptors. Humans have seventeen families of proper olfactory receptors (ORs), numbered 1 through 14, 51, 52, and 56, plus two other families of receptor that are also involved in smelling alongside the ORs. The names are derived largely from Greek, but with contributions from other languages as well. The syllables are designed to be as odor-neutral as possible for English speakers. A few syllables have been chosen from Gaulish, since it is a language of what is now France and since French figures prominently in fragrance naming, and since most modern day persons would be unfamiliar with it and therefore would be unlikely to have preconceived odor associations with the words.

Family Syllable Origin
OR1 vel Lat. vēlum, veil, for the light, airy, fresh, clean, and powdery notes of OR1D2, OR1G1, and OR1N2 agonists.
OR2 cort Lat. cortex, bark, for the cortexy green-stemmy note of OR2AG1 and OR2AG2 agonists.
OR3 sub Lat. sūber, cork, for the OR3A1 agonists that cause cork taint in wines.
OR4 cyps Gk. κυψέλη, beehive, for the beeswax note of beta-ionone.
OR5 ther Gk. θερμός, warm, and θηρίον, animal, for the warmed/gently heated note of OR5P3 agonists and the animalic note of OR5A2/OR5AN1 agonists.
OR6 marth Gk. μάραθον, fennel, for OR6C70's response to an anisic odorant.
OR7 xyl Gk. ξύλον, wood, for OR7A17 agonists having a woody APQ.
OR8 rhad Gk. ῥαδινάκη, a certain kind of petroleum, for the bright naphthyl- or petrol-like note of OR8H1 agonists that is quenched by adding an inverse agonist.
OR9 lot Lat. lōtium, urine, for OR9Q2's response to urinous-smelling p-cresol and its esters.
OR10 nant Gaul. nanto-, valley, for OR10J5 agonists having a lily-of-the-valley character.
OR11 plyn Gk. πλύνειν, to wash, for the clean-and-dirty-laundry odors of OR11H agonists and the "smelling water" faculty of OR11A1.
OR12 styph Gk. στυφός, pungent, for OR12D2's response to acids.
OR13 run Gaul. runo-, mystery, for the fact that no strong agonist is known of any OR13 receptor.
OR14 daph Gk. έδαφος, floor, for OR14J1's response to earthy-humus odorants.
OR51 xill Lat. axilla, armpit, for the axillary sweat odorant 3-methyl-2-hexenoic acid, which is an agonist of some of the OR51 receptors.
OR52 mult Gaul. multon-, root of the word mutton, for OR52A5's response to 4-ethyloctanoic acid, which gives mutton and goat cheese a characteristic flavor note.
OR56 chal Gk. χαλασμένος, rancid, since some of the OR56 receptors correlate to rancid odors.
TAAR chthy Gk. ἰχθύς, fish, for the response of TAAR5 to trimethylamine.
VN1R delge Gaul delgo-, to hold, since the VN1Rs are descended from ancestral pheromone receptors, and the VN1R1 agonist hedione produces a cozy, huggable feeling.

In all of the above syllables, and the elements we'll be adding onto them later, ch is pronounced as in Bach, however you say that ch is how you would say ch in the coined words. The vowels of sub, xyl, lot, plyn, and run are all long: "sube", "gz-aisle", "loat", "pline", "roon".


Indicating Subfamilies

Each family of OR is divided into one or more subfamilies, indicated with letters of the alphabet, e.g. OR1D, OR2M, OR3A, and so on. Onto the family syllables are added adjectival endings indicating the subfamily, except for chthy and delge since TAAR and VN1R have no subfamilies.

Subfamily Ending Subfamily Ending Subfamily Ending
A -aceous J -idge T -est
B -(i)ble K -ski U -ure
C -ique L -elle V -ive
D -id M -eme W -ow
E -ese N -ine X -ix
F -ful P -plete Y -y
G -gry Q -esque Z -azzle
H -ach R -er    
I -illic S -ous    

Admittedly, not all of these endings are already adjectival endings, but with so many letters, some creative license was called for. There is no ending for O since no human OR has the subfamily O. Any time two elements would create a difficult juxtaposition of consonants, a short letter I may be inserted for ease of pronunciation.

This is enough to construct a few names already, such as nantigry for the balsamic OR10G note, subaceous for the OR3A note, veligry for the aforementioned smooth waxiness of OR1G1, and daphidge for the OR14J1 humus note. All of these subfamilies have either only one member or all their members probably contribute the same APQ, so only the family and subfamily must be specified. NOSES adjectives may sound strange at first, but this is by design; not only does this minimize the potential for preexisting odor associations, but it is also easier to remember a word like nantigry than a more traditionally made compound like heptalilivalligammic.


Extended Subfamilies

A handful of receptors have two-letter subfamily codes; these and their endings are:

AC -acic AJ -ajic AR -ar
AD -adous AK -akik AS -ase
AE -aeous AN (not necessary) AT -ate
AG -ageous AP -apic AU -oic

The subfamily code AN occurs only in OR5AN1, whose APQ is the same as that of OR5A2, therefore the two receptors share the same APQ name, therefore no ending is required for AN.

Among the NOSES names constructible at this step are theracic (OR5AC2), probably a tropical-fruit APQ; cortageous, the aforementioned stemmy-cortex APQ; cortate, a component of the odor of sandalore but not santalol, probably a pine-like sharpness; and theroic, part of the aroma of coconut that distinguishes it from other lactonics.


Member-Level Naming

Sometimes it is necessary to differentiate between members of a subfamily, since they would be expected to have different APQs. It is also necessary to distinguish members of the TAAR and VN1R families. Members are indicated with a number; each number can be assigned a prefix. By using an obscure ancient language, we can avoid any associations that might arise from traditional Latin or Greek prefixes like proto- or tri-. One obscure ancient language that still lets us maintain a connection to the present-day land of perfumery is Gaulish, so it is from that language the first nine prefixes are taken:

Number Prefix Number Prefix Number Prefix
1 tux- 4 pet- 7 se-
2 cil- 5 pem- 8 o-
3 te- 6 swe- 9 na-

The combination of te- + nant- adds an R between elements to avoid sounding like the word "tenant".

Now it is possible to distinguish the APQ of OR1A1, whatever that might be, from that of OR1A2, whatever that might be: tuxvelaceous and cilvelaceous. Also, this is now enough of a framework on which to build the word for the OR5A2/OR5AN1 animalic facet of muskiness: ciltheraceous, as distinguished from the pleasant-floral tuxtheraceous OR5A1 aspect of ionone.

Numbers ten through sixteen are derived from French, except spelled phonetically for English.

Number Prefix Number Prefix
10 diz- 14 torz-
11 onz- 15 kinz-
12 duz- 16 siz-
13 trez-    

With these numbers, duztherble (OR5B12) is an aspect of jasmine notes, probably the celery-like sharpness; dizcortest (OR2T10) is some kind of sweet-fruity APQ; onzcortible (OR2B11) is a nuance common to orange and coffee, though exactly which nuance that is is unclear.

It should be pointed out that NOSES names are assignable without knowledge of what APQ each receptor's activation causes. We infer that these APQs must exist, and we can name them in advance of identifying them, so that the name may be defined later when there is confidence about its meaning beyond a mere gene ID.


Additional Members

Numbers from 17 onward are assigned prefixes that have been chosen in an ad hoc manner. It isn't worth memorizing this last part of the list, because these member numbers are only used in one or two or a few receptors, so knowing the prefixes for numbers 17 and up will be less useful than just memorizing the resulting NOSES names. For reference, here's the list:

Number Prefix Example Origin of prefix
17 quay- ("key") quaytherble (OR5B17) For floralozone, an OR5B17 agonist.
18 eu- eutherid (OR5D18) For eugenol, an OR5D18 agonist.
21 ty- tycypsiful (OR4F21) Gk. τύχη, fortune, from the popular belief that the number 21 is lucky.
24 ambr- ambrixylese (OR7E24) For ambroxan, an OR7E24 agonist.
25 peo- peocortaceous (OR2A25) For peony acetonitrile, an OR2A25 agonist.
27 tern- terncorest (OR2T27) Lat. tertius + Gaul. na-, three nines
29 bu- ("byoo") bucorest (OR2T29) Lat. butyrum, butter, for diacetyl, an OR2T29 agonist.
33 dym- dymcorest (OR2T33) Gk. δίδυμος, twin, since it consists of two of the same numeral.
34 thal- thalcorest (OR2T34) Gk. θάλαττα, sea, for floralozone, an OR2T34 agonist.
35 odd- oddcorest (OR2T35) Both digits are odd.
45 clin- clincypsique (OR4C45) Lat. inclino, by analogy with a 45 degree angle
46 eni- enicypsique (OR4C46) Homage to the ENIAC, which was formally dedicated in 1946.
47 trek- trekcypsaceous (OR4A47) Homage to Star Trek, which uses the number 47 frequently.
65 nilli- nillimarthique (OR6C65) For ethyl vanillin, OR6C65 agonist.
68 king- kingmarthique (OR6C68) Homage to Dr. Martin Luther King, Jr., 1929-1968.
70 ane- anemarthique (OR6C70) For anethole, OR6C70 agonist.
74 logi- logimarthique (OR6C74) Homage to TTL integrated circuits, whose part numbers begin with 74.
75 dran- dranmarthique (OR6C75) Lat. dodrans, three quarters.
76 vi- (with a long I) vimarthique (OR6C76) Homage to the Viking mission to Mars, which landed on the Red Planet in 1976.

Identified NOSES

Here are all the confidently identified NOSES to date, i.e. those to which a perceptual quality has been assigned. In many cases, these perceptual assignments are the result of smelling multiple receptor agonists with and without an antagonist or inverse agonist, and/or smelling multiple dissimilar agonists in rapid rotation to find the common nuance. A few have been assigned by comparing agonist odorants with similar-smelling non-agonists. Some are well supported by evidence that individuals with a faulty receptor perceive a certain compound very differently from those with wild-type alleles, and some are extrapolated from the fact that they respond very specifically to one class of molecules, or one category of odors, or even that they are strongly active for a particular odorant that exhibits a unique APQ absent from similar odors or other molecules in the same class.

THIS LIST IS SUBJECT TO CHANGE.

Name cilvelid
Receptor(s) OR1D2

A light, fresh-clean brightness prominent in bourgeonal as opposed to other muguets, important for lactonic, rose, and sea breeze odors.


Name tevelese
Receptor(s) OR1E3

A plasticky, chemical, petroleum-like overtone some people perceive in the smell of acetophenone.


Name veligry
Receptor(s) OR1G1

A smooth, delicate, almost wax-like note important to rose and lactone odors, and prominent in many candy and floral aromas.


Name cilveline
Receptor(s) OR1N2

The powdery aspect of musk, as is especially prominent in ambrettolide, contrasted with musk's animalic aspect.


Name peocortaceous
Receptor(s) OR2A25

A dried-petal, rosy, tobacco-like nuance prominent in the odors of peony acetonitrile and linalool.


Name sweet
Receptor(s) OR2G2, OR2M4, OR2T10, OR2T34, OR5AC2

The sweetness of vanilla, cinnamon, basil, and fruity notes. Probably a combinatorial code; odors that excite three or more of these receptors smell sweet, while those that excite OR2T10 and OR5AC2 in particular tend to smell fruity.


Name cilcorteme
Receptor(s) OR2M2

A somewhat sulfurous note, vaguely suggestive of cabbage or onion, prominent in the odors of grapefruit and gardenia.


Name tecorteme
Receptor(s) OR2M3

The distinctiveness of onion as compared to other sulfurous odors.


Name secorteme
Receptor(s) OR2M7

A cabbage-like note perceivable by some people in the smells of citronella, geranium, and the urine produced by certain individuals after eating asparagus.


Name cortest
Receptor(s) OR2T1, OR2T2, OR2T6, OR2T8, OR2T11, probably others in the OR2T subfamily, and possibly OR2C1?

The sulfurous smell, a stinking facet of eggs, garlic, sulfur, skunk, and sewage. It is possible that all five receptors convey different sulfurous qualities, or they may all produce the same APQ.


Name tecortow
Receptor(s) OR2W3

A zesty facet dominant in citrus peel aromas, but also present in geranium, vanilla, clove, and beta-ionone.


Name cortageous / tuxcortageous / cilcortageous
Receptor(s) OR2AG1, OR2AG2

Probably one in the same nuance, in which case the name cortageous applies. A sharp stemmy-green-leafy aspect important to rose, banana, bell pepper, and leaf alcohol aromas.


Name cortate
Receptor(s) OR2AT4

A sharp note in the odor of sandalore, brahmanol, and, weakly, in that of sandranol, but absent from other sandalwood odors, and quenched by addition of raspberry ketone or phenirat, probably a pine-like brightness.


Name subaceous
Receptor(s) OR3A1, OR3A2, OR3A3, OR3A4

That distinctiveness of peas that distinguishes them from other legumes; the wet-dog-like aspect of carrots, newspaper, cork taint, certain musty/moldy odors, and garbage.


Name cilcypski
Receptor(s) OR4K2

A textured, plushy, comfy-sweater aspect of almond/cherry, malty/cereal, clove, and certain musks.


Name pemcypsine, marthaceous
Receptor(s) OR4N5, OR6A2

Probably two different nuances. Each of these is implicated as the unpleasant soapy or stinkbug note some individuals perceive in the odor and taste of cilantro (coriander leaf).


Name cypsiplete
Receptor(s) OR4P4

The distinctive laundered-cloth aspect of the odor of the musk compound habanolide.


Name tecypsesque
Receptor(s) OR4Q3

A bottomy, clovey, pizza-like aspect of garlic, grape, and clove.


Name tuxtheraceous
Receptor(s) OR5A1

A pleasant floral note some individuals perceive in the odor of beta-ionone.


Name ciltheraceous
Receptor(s) OR5A2, OR5AN1

The distinctive animalic aspect of musk odors, as contrasted with any powdery, fruity, watery, floral, greasy, or other notes.


Name duztherble
Receptor(s) OR5B12, OR5B17

Probably the same nuance for both receptors. Perhaps the celery-like aspect of jasmine and ozone, or perhaps the pink-floral quality common to jasmonyl, eugenyl acetate, and concentrated floralozone.


Name tuxtherski
Receptor(s) OR5K1

The common note of all alkylpyrazines and alkoxypyrazines, dominant in peanut, hazelnut, cocoa, bean, pea, bell pepper, and beef aromas; a nuance at the intersection of nutty, earthy, and dried-leaf notes.


Name tethereme
Receptor(s) OR5M3

The distinctiveness of sugary, caramellic, cotton candy, and berry odors.


Name tetherplete
Receptor(s) OR5P3

A warmed-up aspect, suggestive of something that has been gently heated but not burned.


Name theroic
Receptor(s) OR5AU1

Distinctiveness of coconut as contrasted with other lactonic aromas such as milk, peach, hay, etc.


Name anemarthique
Receptor(s) OR6C70

Distinctiveness of anisic odors as contrasted with other sweet balsamic odors.


Name marthiplete
Receptor(s) OR6P1

The common note between cherry/almond and hyacinth; a dark floral-like aspect.


Name dizxylaceous
Receptor(s) OR7A10

Distinctiveness of black pepper; a peppery-spicy aspect unlike the spiciness of cinnamon, clove, nutmeg, etc.


Name quayxylaceous
Receptor(s) OR7A17

The woody note; the most prominent note in the odor of arborone or Iso-E-Super, also perceptible in ambergris, vanilla, grapefruit, and patchouli.


Name petixylid
Receptor(s) OR7D4

The unpleasant urine-like note some individuals perceive in the odor of androstenone.


Name xylese
Receptor(s) OR7E24

Distinctiveness of ambergris; the aspect of ambroxan's odor that distinguishes it from other woody odors.


Name orhadible
Receptor(s) OR8B8, OR8B12

Distinctiveness of mint; a nuance common to peppermint, spearmint, and wintergreen.


Name tuxrhadid
Receptor(s) OR8D1

The burned aspect of certain caramellic odors.


Name tuxrhadach
Receptor(s) OR8H1

A bright, sparkly, almost petroleum-like note in naphthyl, vanilla, peony, white-floral, and spearmint odors.


Name rhadski
Receptor(s) OR8K1, OR8K3, OR8K5

A tobacco-like or plum-like nuance also prominent in the odor of peppermint.


Name cillotesque
Receptor(s) OR9Q2

Distinctiveness of urinous, barnyard, or narcissus odors as contrasted with other balsamic, subaceous, therski, or floral odors.


Name swenantaceous
Receptor(s) OR10A6

The full-bodied aspect of floral notes, especially of rose; a perfume-like bottomy aspect that on its own would seem insipid.


Name tenantid
Receptor(s) OR10D3

Distinctiveness of nutmeg (isoeugenol) compared to other clove-like aromas.


Name nantigry
Receptor(s) OR10G3, OR10G4, OR10G6, OR10G7, OR10G9, OR10G2?, OR10G8?

The balsamic note, a quality dominant in whisky, leather, clove, nutmeg, anisic, vanilla, barnyard, and carnation aromas, separate from any alcoholic, animalic, spicy, sweet, nutty, anemarthique, creamy, urinous, or floral notes.


Name pemnantidge
Receptor(s) OR10J5

Distinctiveness of muguet or lily-of-the-valley odors such as lilial, lyral, bourgeonal, hivernal, nympheal, etc., a coarse-textured styrofoamy aspect separate from any floral, clean, bright, piney, fresh, waxy, aldehydic, or rubber balloon notes.


Name plynaceous
Receptor(s) OR11A1

A wet-rock chalkiness as of very dilute petrichor (rain); the wet-clean apsect of earthy notes; a chalky-powdery-mildewy aspect of certain molds.


Name plynach
Receptor(s) OR11H4, OR11H6, OR11H12, OR11H1?, OR11H2?

A floral-clean-laundry aspect of rose, orangeflower, spearmint, acetophenone, and tonka/hay (coumarin).


Name seplynach
Receptor(s) OR11H7

The unpleasantness of isovaleric acid, for those individuals who are especially sensitive to it.


Name cilstyphid
Receptor(s) OR12D2

Probably a sour note, the tartness of vinegar and isovaleric acid.


Name daphidge
Receptor(s) OR14J1

The humus aspect of concentrated geosmin and 2-ethyl fenchol, also prominent in the odor of patchouli.


Name tuxillese
Receptor(s) OR51E1

A note prominent in sour milk, buttermilk, cheeses especially American and Cheddar, as well as in the odor of garbage.


Name cilxillese
Receptor(s) OR51E2

Distinctiveness of vinegar; that aspect that distinguishes formic, acetic, propionic, and butyric acids from other short-chain fatty acids, that vinegar-like aspect perceptible in the odor of beta-ionone.


Name xillelle
Receptor(s) OR51L1

Distinctiveness of honey; that syrupy quality which is uniquely honeyed as contrasted with the pruny, sweet, and balsamic aspects of same.


Name pemmultaceous
Receptor(s) OR52A5

The gyro note; that distinctive note in lamb meat and goat cheese that is lacking in analogous cattle products.


Name multid
Receptor(s) OR52D1

A painty, ethereal, or estery note; a widespread facet of fruity, sweet, cheesy, and solventy odors.


Name omultese
Receptor(s) OR52E8

The cumin-like aspect of body odor, or the funky aspect of cumin.


Name pechthy
Receptor(s) TAAR5

Distinctiveness of raw fish or prawns, separate from any metallic, aldehydic, marine, cucmber, or popcorn-like notes.


Name swechthy, ochthy
Receptor(s) TAAR6, TAAR8

Likely to be two separate APQs. Together these account for most of the smell of putrescine or cadaverine, described as the smell of decay but actually more of a wet animal fur quality.


Name tuxdelge
Receptor(s) VN1R1

A facet that is felt more than smelt, namely, the cozy-cuddly effect of dilute hedione.


Practical Application

Businesses which sell food, beverages, or fragrances are invited to use NOSES to describe and categorize their products, and to run promotions offering customers a small discount or freebie for correctly demonstrating knowledge of NOSES, for example answering a multiple-choice question like "which of the following ingredients smells/tastes orhadible" or requesting an item by taste such as "I'm in the mood for something pemmultaceous".

Complete List

Here is the complete, auto-generated list of odor receptors and their names under the proposed system:

TODO: