What does nut mean?
A nut has several distinct but recognizable meanings. Most commonly, it is a hard-shelled seed with an edible kernel, as in walnuts, almonds, and hazelnuts. In engineering, a nut is a small threaded metal fitting that tightens onto a bolt. Informal English also uses the word for a person's head, with expressions such as “a tough nut to crack,” and, in the plural, for testicles or for an eccentric person. The mechanical sense is firmly established in technical and everyday language, while the figurative senses are more conversational and can be playful or insulting depending on context. Because the word links an organic seed, a metal fastener, and several vivid figurative ideas, it appears in idioms and compounds such as “the nuts and bolts” and “nutmeg.” Its range of meanings makes it useful both as a precise noun and as a source of familiar expressions.
nounA nut is a hard-shelled seed whose edible kernel is often eaten, and by extension a small metal fastener, typically with a threaded hole. In informal use, it can also mean a person's head or, in the plural, a testicle.
- A hard-shelled seed with an edible kernel, such as a walnut, almond, or hazelnut.
- A small metal fastener with a threaded hole, used to secure a bolt or screw.
- Informal, sometimes insulting: a person's head.
- Informal, usually in the plural: a testicle.
- Informal, often in the plural: a crazy or eccentric person.
"She cracked the walnut and found a small piece of shell inside."
"The recipe calls for a handful of mixed nuts and a drizzle of honey."
"Use a wrench to tighten the nut onto the bolt."
"That idea is a tough nut to crack."
The regular plural is used for multiple seeds or fasteners. Informally, “nuts” can mean testicles or refer to crazy people; the testicle sense is vulgar in many contexts.
"The bowl was filled with salted nuts."
One ordinary word can mean an edible seed, a metal fastener, a head, and even a testicle: language keeps turning hard things into useful ones.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does nut come from?
The word descends from Old English hnutu, an inherited Germanic word for a hard seed or similar object. The English form was influenced in its development by the cluster of nut words found across Germanic languages, including German Nuss and Dutch noot. The Latin nux, meaning “nut” and the source of words such as nucleus and nuclear, is a separate but related etymological parallel rather than the direct source of the English word.
Related word forms
How nut is actually used
The word is neutral and standard for both edible seeds and mechanical fasteners. The senses meaning “head,” “testicle,” and “crazy person” are informal; the plural sense referring to testicles is vulgar in many contexts.
Easily confused with nut
A bolt is a threaded metal fastener with a hexagonal head, whereas a nut is the separate threaded piece that fits onto it.
A seed is the reproductive unit of a plant, while a nut is a particular hard-shelled, usually edible seed.