nut

¹ American  

[nuht] / nʌt /

noun

1. a dry fruit consisting of an edible kernel or meat enclosed in a woody or leathery shell.

2. the kernel itself.

3. Botany. a hard, indehiscent, one-seeded fruit, as the chestnut or the acorn.

4. any of various devices or ornaments resembling a nut.

5. a block, usually of metal and generally square or hexagonal, perforated with a threaded hole so that it can be screwed down on a bolt to hold together objects through which the bolt passes.

6. Slang. the head.

7. Slang.

   1. a person who is very enthusiastic about something; buff; enthusiast; devotee.

      He's a real circus nut.

   2. an extremely concerned or zealous person.

      My boss is a nut on double-checking everything.

8. Slang.

   1. a foolish, silly, or eccentric person.

   2. an insane person; psychotic.

9. Slang: Vulgar. a testis.

10. Informal.

    1. the operating expenses, usually figured weekly, of a theatrical production or other commercial enterprise; a break-even point.

    2. the total cost of producing a theatrical production or of forming and opening any new business venture.

11. Music. (in instruments of the violin family)

    1. the ledge, as of ebony, at the upper end of the fingerboard, over which the strings pass.

    2. the movable piece at the lower end of the bow, by means of which the hairs may be slackened or tightened.

12. Printing. en.

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verb (used without object)

nutted, nutting

1. to seek for or gather nuts.

   to go nutting in late autumn.

idioms

1. off one's nut,

   1. Sometimes Offensive. foolish, silly, or insane.

   2. confused; unreasonable.

   3. mistaken or wrong.

      You're off your nut if you think such a plan can succeed.

2. hard nut to crack, Also tough nut to crack

   1. a problem difficult to solve; a formidable undertaking.

   2. a person difficult to know, understand, or convince.

3. from soup to nuts. soup.

Nut ² American  

[noot] / nut /

noun

Egyptian Religion.

1. the goddess of the sky, sometimes shown as a cow bearing Ra on her back and the stars on her underside.

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N.U.T. ³ American  

abbreviation

British.

1. National Union of Teachers.

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NUT ¹ British  

abbreviation

1. National Union of Teachers

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nut ² British  

/ nʌt /

noun

1. a dry one-seeded indehiscent fruit that usually possesses a woody wall

2. (not in technical use) any similar fruit, such as the walnut, having a hard shell and an edible kernel

3. the edible kernel of such a fruit

4. slang

   1. an eccentric person

   2. a person who is mentally disturbed

5. a slang word for head

6. slang to be extremely angry; go into a rage

7. slang mad, crazy, or foolish

8. a person or thing that presents difficulties (esp in the phrase a tough or hard nut to crack )

9. a small square or hexagonal block, usu. metal, with a threaded hole through the middle for screwing on the end of a bolt

10. Also called: chock.  mountaineering a variously shaped small metal block, usually a wedge or hexagonal prism (originally an ordinary engineer's nut) with a wire or rope loop attached, for jamming into a crack to provide security

11. Also called (US and Canadian): frog.  music

    1. the ledge or ridge at the upper end of the fingerboard of a violin, cello, etc, over which the strings pass to the tuning pegs

    2. the end of a violin bow that is held by the player

12. printing another word for en

13. a small usually gingery biscuit

14. a small piece of coal

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verb

1. (intr) to gather nuts

2. slang (tr) to butt (someone) with the head

nut Scientific  

/ nŭt /

1. A dry, indehiscent simple fruit consisting of one seed surrounded by a hard and thick pericarp (fruit wall). The seed does not adhere to the pericarp but is connected to it by the funiculus. A nut is similar to an achene but larger. Acorns, beechnuts, chestnuts, and hazelnuts are true nuts. Informally, other edible seeds or dry fruits enclosed in a hard or leathery shell are also called nuts, though they are not true nuts. For instance, an almond kernel is actually the seed of a drupe. Its familiar whitish shell is an endocarp found within the greenish fruit of the almond tree. Peanuts are actually individual seeds from a seed pod called a legume.

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nut More Idioms  

More idioms and phrases containing nut

• drive someone crazy (nuts)
• from soup to nuts
• hard nut to crack

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Other Word Forms

• nutlike adjective

Etymology

Origin of nut

before 900; 1900–05 nut for def. 8b; Middle English nute, Old English hnutu; cognate with Dutch noot, German Nuss, Old Norse hnot; akin to Latin nux

Explanation

A nut is a kind of fruit made of a large, edible seed with a very hard shell around it. The nuts that squirrels typically gather (sometimes storing them temporarily in their cheek pouches) are acorns. It might seem strange that a nut is a fruit, since until they've been cracked open, most nuts are as hard and inedible as rocks. Think of the meat of a walnut or almond that hides inside — this is the edible seed within the fruit. If someone calls you a nut, or describes you as nuts or nutty, they think you're crazy or wacky, and when you refer to "a tough nut to crack," you're talking about a tricky problem.

Example Sentences

I am expecting West Ham to play with the kind of intensity that is required but Everton can be a tough nut to crack.

From BBC • Apr. 23, 2026

Hossein, a nearby nut seller, wasn’t happy either.

From Los Angeles Times • Mar. 24, 2026

Suddenly, it’s a nut dessert with a brownie supporting role.

From Salon • Mar. 5, 2026

"It's quite easy to make a version of that story where he's a sort of toxic incel male conspiracy theorist nut who you don't really sympathize with," he told AFP.

From Barron's • Mar. 1, 2026

If it’s for me, I’m a hard nut to crack; and I take it standing up.

From "Dracula" by Bram Stoker

Related Words

• kernel