What it names now
In British English, flavouring is first of all a kitchen noun: a substance, natural or manufactured, added to food or drink so that the mixture tastes of something in particular. Vanilla extract, beef stock powder, and lemon oil are flavourings in that sense. The same spelling is also the present participle of the verb flavour, so a cook can be flavouring a stew while adding a flavouring to it. American English writes flavoring for both uses. The two spellings are one word; they split only on the -our / -or line that also separates colour from color.
The morphology is English and almost too plain to notice. Flavouring is the stem flavour plus -ing, the suffix that makes participles and verbal nouns. The suffix is not borrowed with the stem. What needs explaining is flavour, and then why a word that once meant smell ended as the name of a bottle on a spice shelf.
Built in English, not borrowed as a package
The origin of the word flavouring is a late chapter. The noun meaning an added substance is an early-nineteenth-century formation from the verb, first recorded in cookery. Chronologies do not agree on the year: one well-used account gives 1831, another 1845. That is almost certainly a difference of first citations, not of two separate coinages. By then English had long had flavour as a verb, so the -ing noun was the ordinary next step.
The verb itself is older. In the 1540s it could mean to give something a distinctive quality. Around 1740 it is recorded in the narrower sense of putting a flavouring agent into food. Earlier still, in the fifteenth century, flavour as a verb could mean to smell, a use that has vanished. Middle English also had flauryng as a word for perfume. That form is not the direct ancestor of the modern cookery noun, but it shows that English had already used an -ing derivative in the scent world centuries before Victorian recipes needed a name for extracts and essences.
French smell, English taste
The stem arrived as a borrowing. Late Middle English, around 1300, took flavour from Old French flaor or flaour. In French the word meant smell, odour, the act of smelling, and the sense of smell, and in English at first it meant a smell, usually a pleasing one. It was not a native Old English inheritance. It came in with the French vocabulary of sensation, alongside savour.
Taste is a later overlay. The sense of flavour as savour, the distinctive taste of a food, is first clearly attested in the late seventeenth century, perhaps as early as the 1670s. Early uses treat flavour as the part of taste that depends on smell. That is a precise claim, not a metaphor: much of what English speakers call taste is retronasal olfaction. From that specialised start the noun widened to the combined sensation, to a particular variety of it, a lemon flavour or ten flavours of yogurt, and then figuratively to the characteristic quality of a place, a period, or a type of thing.
The word sat in English for a long time before it became ordinary. One older dictionary remarked that the noun was uncommon before Milton, and that Milton’s own use is hard to pin down. Whether or not that judgement still holds, it is a useful caution: the medieval loan spent centuries as a smell-word before it became the everyday taste-word.
Breath, blowing, and a disputed stench
Old French flaor is usually traced to Vulgar Latin flator, an odour understood as something that blows. Classical Latin already had flator, a blower, from the verb flare, to blow or puff. Some accounts take Latin flatus, a blowing, breeze, or breath, as the more immediate base. Either way the picture is the same: smell as air in motion.
That Latin verb is related to native English blow. The two are distant doublets, one through Romance, one through Germanic, both from a Proto-Indo-European root for blowing. A Romance sibling often cited is Old Italian fiatore, a bad odour, which suggests that the spoken Latin word did not always name a pleasant scent.
Here the handbooks part company. A number of Oxford-style etymologies propose that the French word may mix flatus with Latin foetor, stench. That would make the odour meaning easier to explain, because a word for blowing would have been pulled toward a word for foul smell. The blend is not demonstrated. It remains a live uncertainty, and nothing in the later English history depends on settling it.
The inserted v, and the British u
Old French wrote flaor, without v. Middle English inserted the consonant, almost certainly under the influence of savour, already the English word for taste. Some descriptions call the change euphonic; analogy with a neighbouring sense-word is the more concrete mechanism. Once flavour and savour looked alike, they were ready to share semantic space when flavour moved from nose to palate.
The British -our in flavouring is the usual later-medieval spelling that English kept in honour and colour. American flavoring follows the -or reform associated with Noah Webster and early-nineteenth-century American dictionaries. Both spellings existed in Britain for a long time; the modern national split is a standardisation, not two roots.
A perfume that became an additive
The fact that locks the history in place is small and specific. Middle English flauryng meant perfume. Modern flavouring, dated to the 1830s or 1840s, means a substance you stir into food. Same suffix, same stem, different job. Between those two -ing words the stem had shifted from air to taste, the verb had learned to mean season, and industrial cookery needed a countable name for the agent. The bottle on the shelf still does, in a quiet way, what the Latin blower did: it sends a smell toward the nose, and English now calls that a flavour.