Online Etymology Dictionary

nut-cracker (n.): also nutcracker, 1540s, from nut (n.) + agent noun from crack (v.).
nutation (n.): 1610s, "action of nodding," from Latin nutationem (nominative nutatio), noun of action from past participle stem of nutare "to nod," from PIE *neu- "to nod" (see numinous). Astronomical use is from 1715. Related: Nutational.
nuthatch (n.): mid-14c., probably so called from its habit of breaking open and eating nuts; from nut + second element related to hack (v.) and hatchet.
nutmeg (n.): "hard aromatic seed of the East Indies," c. 1300, from Old North French or Anglo-French *noiz mugue, from Old French nois muguete, unexplained alteration of nois muscade "nut smelling like musk," from nois "nut" (from Latin nux) + Latin muscada, fem. of muscat "musky" (see muscat). Probably influenced in English by Medieval Latin nux maga (compare unaltered Dutch muskaatnoot, German muscatnuß, Swedish muskotnöt).

American English colloquial wooden nutmeg "anything false or fraudulent" is from 1830. Connecticut is called the Nutmeg State "in allusion to the story that wooden nutmegs are there manufactured for exportation." [John Russell Bartlett, "Dictionary of Americanisms," 1859]
nutria (n.): 1836, from Spanish nutria "otter," also lutria, from Latin lutra (see otter).
nutrient (n.): "a nutritious substance," 1828, noun use of adjective (1640s) meaning "providing nourishment," from Latin nutrientem (nominative nutriens), present participle of nutrire "to nourish, suckle, feed, foster" (see nourish).
nutriment (n.): 1540s, from Latin nutrimentum "nourishment; support," from nutrire "to nourish, suckle, feed," from PIE *nu-tri-, from root *(s)nau- "to swim, flow, let flow," hence "to suckle" (source also of Sanskrit snauti "she drips, gives milk;" Greek nan "I flow"), extended form of root *sna- "to swim" (see natatorium).
nutrition (n.): early 15c., from Old French nutrition (14c.) and directly from Latin nutritionem (nominative nutritio) "a nourishing," noun of action from past participle stem of nutrire "to nourish, suckle" (see nourish).
nutritionist (n.): 1926, from nutrition + -ist.
nutritious (adj.): 1660s, from Latin nutricius "that which nourishes, nurses," from nutrix (genitive nutricis) "a nurse," from nutrire (see nourish). Related: Nutritiously.
nutritive (adj.): late 14c., from Old French nutritif and directly from Medieval Latin nutritivus "nourishing," from past participle stem of Latin nutrire "to nourish" (see nourish).
nuts (adj.): "crazy," 1846, from earlier be nutts upon "be very fond of" (1785), which is possibly from nuts (plural noun) "any source of pleasure" (1610s), from nut (q.v.). Sense influenced probably by metaphoric application of nut to "head" (1846, as in to be off one's nut "be insane," 1860). Nuts as a derisive retort is attested from 1931.

Connection with the slang "testicle" sense has tended to nudge it toward taboo. "On the N.B.C. network, it is forbidden to call any character a nut; you have to call him a screwball." ["New Yorker," Dec. 23, 1950] "Please eliminate the expression 'nuts to you' from Egbert's speech." [Request from the Hays Office regarding the script of "The Bank Dick," 1940] This desire for avoidance accounts for the euphemism nerts (c. 1925).
nutshell (n.): c. 1200, nute-scalen; see nut + shell (n.). Figurative use with reference to "great condensation" (1570s) supposedly originally is a reference to a copy of the "Iliad," mentioned by Pliny, which was so small it could fit into the shell of a nut.
nutter (n.): "one who gathers nuts," late 15c., from nut + -er (1). Meaning "crazy person" is British slang, 1958, from nut + -er (3). Nuttery "mental hospital" is attested from 1931; earlier it meant "place for storing nuts" (1881).
nutting (n.): "action of gathering nuts," 1723, from nut (n.).
nutty (adj.): early 15c., "nut-like," from nut + -y (2). Meaning "crazy" is from 1898 (see nuts); earlier "amorous, in love (with)," 1821. Related: Nuttiness.
nuzzle (v.): early 15c., "to bring the nose to the ground," back-formation from noselyng "on the nose, prostrate," frequentative of nose (v.); meaning "burrow with the nose" is first attested 1520s; that of "lie snug" is from 1590s, influenced by nestle, or by nursle, frequentative of nurse. Related: Nuzzled; nuzzling.
nycto-: before vowels nyct-, word-forming element meaning "night," from Latinized form of Greek nykto-, comb. form of nyx "night" (see night).
nyctophobia (n.): medical Latin, from nycto- "night" + -phobia "fear." Related: Nyctophobic.
nylon (n.): 1938, coined, according to DuPont, from random generic syllable nyl- + -on, common ending in fiber names (compare rayon), said to be ultimately from cotton. Use (in plural) for "nylon stockings" is from 1940.
nylons (n.): 1940; see nylon.
nymph (n.): late 14c., "class of semi-divine female beings," from Old French nimphe (13c.), from Latin nympha "nymph, demi-goddess; bride, mistress, young woman," from Greek nymphe "bride, young wife," later "beautiful young woman," then "semi-divine being in the form of a beautiful maiden;" related to Latin nubere "to marry, wed" (see nuptial). Sub-groups include dryads, hamadryads, naiads, nereids, and oreads. Sense in English of "young woman, girl" is attested from 1580s. Meaning "insect stage between larva and adult" is recorded from 1570s. Related: Nymphal; nymphean.
nymphette (n.): also nymphet, nymphete, "sexually attractive young girl," 1955, introduced by Vladimir Nabokov (1899-1977) in his novel "Lolita" to describe alluring (in the eyes of some men) girls age 9 to 14; from nymph + diminutive suffix. Used from 17c. in sense "a little nymph."
nympho (n.): 1935, short for nymphomaniac (see nymphomania).
nympholepsy (n.): "frenzy or rapture supposed to take hold of a man upon gazing on a nymph," 1775, coined by Richard Chandler, in "Travels in Greece," from nymph, on model of epilepsy, with second element from stem of Greek lambanein "to take." Especially "an ecstasy or frenzy caused by desire for the unattainable." Ancient Greek had nympholeptos "caught by nymphs." Related: Nympholept; nympholeptic.
nymphomania (n.): 1775, in English translation of "Nymphomania, or a Dissertation Concerning the Furor Uterinus," by French doctor M.D.T. Bienville, coined from Greek nymphe "bride" (see nymph) + mania "madness" (see mania). Perhaps influenced by earlier French nymphomanie. Defined as "a female disease characterized by morbid and uncontrollable sexual desire." Compare also nympholepsy.
nymphomaniac: 1861 (adj.), 1867 (n.), from nymphomania.
nystagmus (n.): medical Latin, from Greek nystagmos "nodding, drowsiness," from nystazein "to nod, be sleepy," from PIE *sneud(h)- "to be sleepy."