nurture (v.) Look up nurture at Dictionary.com
"to feed or nourish," early 15c., from nurture (n.). Related: Nurtured; nurturing.
nut (n.) Look up nut at Dictionary.com
"hard seed," Old English hnutu, from Proto-Germanic *hnut- (cognates: Old Norse hnot, Dutch noot, Old High German hnuz, German nuß "nut"), from PIE *kneu- "nut" (cognates: 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.
nut-cracker (n.) Look up nut-cracker at Dictionary.com
also nutcracker, 1540s, from nut (n.) + agent noun from crack (v.).
nutation (n.) Look up nutation at Dictionary.com
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.) Look up nuthatch at Dictionary.com
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.) Look up nutmeg at Dictionary.com
"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.) Look up nutria at Dictionary.com
1836, from Spanish nutria "otter," also lutria, from Latin lutra (see otter).
nutrient (n.) Look up nutrient at Dictionary.com
"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.) Look up nutriment at Dictionary.com
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" (cognates: Sanskrit snauti "she drips, gives milk;" Greek nan "I flow"), extended form of root *sna- "to swim" (see natatorium).
nutrition (n.) Look up nutrition at Dictionary.com
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.) Look up nutritionist at Dictionary.com
1926, from nutrition + -ist.
nutritious (adj.) Look up nutritious at Dictionary.com
1660s, from Latin nutricius "that which nourishes, nurses," from nutrix (genitive nutricis) "a nurse," from nutrire (see nourish). Related: Nutritiously.
nutritive (adj.) Look up nutritive at Dictionary.com
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.) Look up nuts at Dictionary.com
"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.) Look up nutshell at Dictionary.com
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.) Look up nutter at Dictionary.com
"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.) Look up nutting at Dictionary.com
"action of gathering nuts," 1723, from nut (n.).
nutty (adj.) Look up nutty at Dictionary.com
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.) Look up nuzzle at Dictionary.com
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- Look up nycto- at Dictionary.com
before vowels nyct-, word-forming element meaning "night," from Latinized form of Greek nykto-, comb. form of nyx "night" (see night).
nyctophobia (n.) Look up nyctophobia at Dictionary.com
medical Latin, from nycto- "night" + -phobia "fear." Related: Nyctophobic.
nylon (n.) Look up nylon at Dictionary.com
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.) Look up nylons at Dictionary.com
1940; see nylon.
nymph (n.) Look up nymph at Dictionary.com
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.) Look up nymphette at Dictionary.com
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.) Look up nympho at Dictionary.com
1935, short for nymphomaniac (see nymphomania).
nympholepsy (n.) Look up nympholepsy at Dictionary.com
"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.) Look up nymphomania at Dictionary.com
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 Look up nymphomaniac at Dictionary.com
1861 (adj.), 1867 (n.), from nymphomania.
nystagmus (n.) Look up nystagmus at Dictionary.com
medical Latin, from Greek nystagmos "nodding, drowsiness," from nystazein "to nod, be sleepy," from PIE *sneud(h)- "to be sleepy."