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nut

[nuht]
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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(def 2).
verb (used without object), nut·ted, nut·ting.
  1. to seek for or gather nuts: to go nutting in late autumn.
Idioms
  1. from soup to nuts. soup(def 7).
  2. hard nut to crack,
    1. a problem difficult to solve; a formidable undertaking.
    2. a person difficult to know, understand, or convince.
    Also tough nut to crack.
  3. off one's nut, Slang.
    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.

Origin of nut

before 900; 1900–05 for def 8b; Middle English nute, Old English hnutu; cognate with Dutch noot, German Nuss, Old Norse hnot; akin to Latin nux
Related formsnut·like, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
British Dictionary definitions for hard nut to crack

NUT

abbreviation for (in Britain)
  1. National Union of Teachers

nut

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 (def. 1)
  6. do one's nut British slang to be extremely angry; go into a rage
  7. off one's nut 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. 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 securityAlso called: chock
  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. British a small piece of coal
verb nuts, nutting or nutted
  1. (intr) to gather nuts
  2. (tr) slang to butt (someone) with the head
See also nuts
Derived Formsnutlike, adjective

Word Origin

Old English hnutu; related to Old Norse hnot, Old High German hnuz (German Nuss)
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for hard nut to crack

nut

n.

"hard seed," Old English hnutu, from Proto-Germanic *khnut- (cf. Old Norse hnot, Dutch noot, Old High German hnuz, German nuß "nut"), from PIE *kneu- "nut" (cf. Latin nux; see nucleus). Sense of "testicle" is attested from 1915. Nut-brown is from c.1300 of animals; c.1500 of complexions of women.

Meaning "crazy person, crank" is attested from 1903, (British form nutter first attested 1958; nut-case is from 1959); see nuts. American English slang sense of "amount of money required for something" is first recorded 1912. The nut that goes onto a bolt is first recorded 1610s (used of other small mechanical pieces since early 15c.). Nuts and bolts "fundamentals" is from 1960.

Online Etymology Dictionary, © 2010 Douglas Harper

hard nut to crack in Science

nut

[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.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Idioms and Phrases with hard nut to crack

hard nut to crack

Also, tough nut to crack. A difficult problem; also, an individual who is difficult to deal with. For example, This assignment is a hard nut to crack, or It won't be easy getting her approval; she's a tough nut to crack. This metaphoric expression alludes to hard-shelled nuts like walnuts. [Early 1700s]

nut

In addition to the idioms beginning with nuts

also see:

The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.