"the fruit of certain trees and shrubs which have the seed enclosed in a woody covering not opening when ripe," Middle English note, from Old English hnutu, from Proto-Germanic *hnut- (source also of Old Norse hnot, Dutch noot, Old High German hnuz, German Nuss "nut"), from PIE *kneu- "nut" (source also of Latin nux; see nucleus).
Sense of "testicle" is attested by 1915 (nuts). Nut-brown "brown as a ripe, dried nut" is from c. 1300 of animals; c. 1500 of complexions of women. The mechanical nut that goes onto a bolt is first recorded 1610s, from some fancied resemblance (nut was used of other small mechanical pieces since early 15c.). The figurative nuts and bolts "fundamentals" is by 1952. The American English slang sense of "amount of money required for something" is recorded by 1912.
Meaning "crazy person, crank" is attested from 1903; British form nutter is attested by 1958. Nut-case "crazy person" is from 1959; nut-house "insane asylum" is by 1929. For more on this sense, see nuts. In slang, nut also meant "fashionable or showy young man of affected elegance" [OED], 1904.
also nutcracker, "instrument used for cracking hard-shelled nuts," 1540s, from nut (n.) + agent noun from crack (v.). Hence also "toy having a grotesque human head, in the mouth of which a nut is placed to be cracked by a screw or lever." The ballet was first performed in 1892, based on Dumas père's rendition of E.T.A. Hoffmann's 1816 story "Nussknacker und Mausekönig."
"sweetmeat made of almonds and other nuts," 1827, from French nougat (18c.), from Provençal nougat "cake made with almonds," from Old Provençal nogat "nutcake," from noga, nuga "nut," from Vulgar Latin *nucatum (nominative *nuca), from Latin nux (genitive nucis) "nut," from PIE *kneu- "nut" (see nucleus).
1590s, "nut of the pistachio tree," from Italian pistacchio, from Latin pistacium "pistachio nut," from Greek pistakion "pistachio nut," from pistakē "pistachio tree," from Persian pistah "pistachio." Borrowed earlier in English as pystace, pistace (mid-15c.), from Old French pistace (13c.) and Medieval Latin pistacia, ultimately from the same source.
1704, "kernel of a nut;" 1708, "head of a comet;" from Latin nucleus "kernel," from nucula "little nut," diminutive of nux (genitive nucis) "nut," from PIE *kneu- "nut" (source also of Middle Irish cnu, Welsh cneuen, Middle Breton knoen "nut," Old Norse hnot, Old English hnutu "nut").
The general sense of "central mass or thing, about which others cluster or matter collects," is from 1762. In biology, "dense, typically rounded structure in a cell, bounded by membranes," from 1831. Later they were found to contain the genetic material. Modern meaning in physics, "positively charged central core of an atom," is from 1912, by Ernest Rutherford, though theoretical use for "central point of an atom" is from 1844, in Faraday.
"action of gathering nuts," 1723, verbal noun from nut (v.) "to gather nuts" (c. 1600), from nut (n.).
Old English walhnutu "nut of the walnut tree," literally "foreign nut," from wealh "foreign" (see Welsh) + hnutu (see nut). Compare Old Norse valhnot, Middle Low German walnut, Middle Dutch walnote, Dutch walnoot, German Walnuss. So called because it was introduced from Gaul and Italy, distinguishing it from the native hazel nut. Compare the Late Latin name for it, nux Gallica, literally "Gaulish nut." Applied to the tree itself from 1600 (earlier walnut tree, c. 1400).