What does bonnet mean?
Bonnet is a noun with two principal lives: it names a soft hat, classically one with a brim framing the face and strings tied beneath the chin, once an essential item of women's outdoor dress and still standard wear for babies; and, in British English, it denotes the hinged metal panel that covers a car's engine, what American speakers call the hood. The word carries strong period associations — think Regency novels and Victorian promenades — yet remains current in nursery wear and motoring vocabulary. Idiomatically, 'to have a bee in one's bonnet' means to nurse a persistent, sometimes obsessive idea, a phrase that has kept the word lively in everyday speech. In Scotland, a variant pronunciation, 'bunnet', refers to the flat woollen cap long associated with working men. Whether describing a baby's frilled headwear, a car engine bay, or a stubborn fixation, bonnet is a small word with a remarkably wide cultural footprint across centuries of dress, driving, and idiom.
A soft hat, typically with a brim at the back and sides, tied under the chin, worn especially by women and children in past eras and by babies today.
"The christening gown came complete with a lace-trimmed bonnet."
The historical women's sense now reads as period or costume language; the baby's sense is fully current.
British term for the hinged metal cover over a car's engine, equivalent to the American 'hood'.
"Steam was rising from the bonnet, so she pulled over and waited for the engine to cool."
Distinctly British; American readers expect 'hood' in this context.
To strike someone on the head (dated).
"In older ballads, rivals sometimes threaten to bonnet each other soundly."
Rare and archaic; encountered almost only in historical literature.
Standard regular plural, used both for hats (e.g., a row of Victorian bonnets in a museum) and, less often, for multiple car bonnets.
"The costume display featured silk bonnets from the 1860s."
If you have 'a bee in your bonnet', you're obsessed with an idea — an idiom born from the old belief that a real insect trapped under your hat would make you behave erratically.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of bonnet
Bonnet entered English from Old French in the medieval period, where it denoted various kinds of cap or head covering. Its deeper origin is uncertain: many lexicographers connect it to the French adjective bon ('good'), possibly via a Late Latin diminutive such as *bonetum, though this derivation is treated as probable rather than proven. If that link holds, bonnet shares distant kinship with Latin-derived words built on bonus ('good'), such as bonus, bonanza, and bonhomie. The word has carried its core meaning of 'head covering' consistently since Middle English, later branching into the automotive sense in the early twentieth century as motoring developed.
How bonnet is actually used
The baby's-bonnet sense survives most strongly in modern everyday use, while the women's fashion sense is largely historical and appears mainly in period contexts. The car-engine meaning is distinctly British — Americans say 'hood' — so using 'bonnet' for a car immediately signals British usage. The Scottish flat-cap sense ('bunnet') is regional and colloquial. The verb sense, meaning to strike someone on the head, exists but is rare and dated.
Easily confused with bonnet
A beanie is a snug, brimless knit cap worn close to the skull, whereas a bonnet is a softer hat, historically tied under the chin.
In American English 'hood' is the word for a car's engine cover, which British English calls the bonnet.