nine (n.)youdaoicibaDictYouDict[nine 词源字典]
Old English nigen, from Proto-Germanic *niwun (cognates: Old Saxon nigun, Old Frisian niugun, Old Norse niu, Swedish nio, Middle Dutch neghen, Dutch negen, Old High German niun, German neun, Gothic niun "nine"), from PIE newn "nine" (cognates: Sanskrit nava, Avestan nava, Greek ennea, Albanian nende, Latin novem (with change of -n- to -m- by analogy of septem, decem), Lithuanian devnyi, Old Church Slavonic deveti (the Balto-Slavic forms by dissimilation of -n- to -d-), Old Irish noin, Welsh naw).

Nine to five "the average workday" is attested from 1935. Nine days has been proverbial since 14c. for the time which a wonder or novelty holds attention.[nine etymology, nine origin, 英语词源]
ninefoldyoudaoicibaDictYouDict
Old English nigonfeald; see nine + -fold.
ninepins (n.)youdaoicibaDictYouDict
1570s, from nine + plural of pin (n.). From the number of pins to be knocked down.
nines (n.)youdaoicibaDictYouDict
in phrase to the nines "to perfection" (1787) first attested in Burns, apparently preserves the ancient notion of the perfection of the number as three times three (such as the nine Muses).
[T]he Book of St. Albans, in the sections on blasonry, lays great stress on the nines in which all perfect things (orders of angels, virtues, articles of chivalry, differences of coat armour, etc.) occur. [Weekley]
No one seems to consider that it might be a corruption and misdivision of to then anes, literally "for the one (purpose or occasion)," a similar construction to the one that yielded nonce (q.v.).
nineteen (n.)youdaoicibaDictYouDict
late Old English nigontene (Anglian), nigontyne (West Saxon); see nine + -teen.
nineteenth (adj.)youdaoicibaDictYouDict
late 14c., nyntenthe; from nineteen + -th (1); a replacement or modification of nigonteoþa, from Old English nigon-teoða. Nineteenth hole "bar-room in a golf clubhouse" is attested from 1901.
nineties (n.)youdaoicibaDictYouDict
1857 as the years of someone's life between 90 and 99; from 1848 as the tenth decade of years in a given century; 1849 with reference to Fahrenheit temperature. See ninety.
Many still live who remember those days; if the old men cannot tell you the exact date, they will say: 'It were in the nineties;' (etc.) ["Chambers's Journal," Nov. 1, 1856]
In Britain, the naughty nineties was a popular name 1920s-30s for the 1890s, based on the notion of a relaxing of morality and mood in contrast to earlier Victorian times. In U.S., gay nineties in reference to the same decade is attested from 1927, and was the title of a regular nostalgia feature in "Life" magazine about that time.
The long, dreary blue-law Sunday afternoons were periods of the Nineties which no amount of rosy retrospect will ever be able to recall as gay, especially to a normal healthy boy to whom all activities were taboo except G. A. Henty and the bound volumes of Leslie's Weekly of the Civil War. [Life, Sept. 1, 1927]
ninetieth (adj.)youdaoicibaDictYouDict
late 14c., nyntithe, from ninety + -th (1); a replacement or modification of Old English nigenteoþan.
ninety (n.)youdaoicibaDictYouDict
Old English nigontig, from nine + -tig "group of ten" (see -ty (1)). Cognate with Old Frisian niontich, Middle Dutch negentich, Dutch negentig, German neunzig.
ninny (n.)youdaoicibaDictYouDict
"simpleton, fool," 1590s, perhaps a misdivision of an innocent (see N for other examples), or from the pet form of the proper name Innocent, with sense influenced by the name's literal meaning. There may be some influence in the word of Italian ninno "baby, child."
ninnyhammer (n.)youdaoicibaDictYouDict
also ninny-hammer, "simpleton," 1590s, from ninny + hammer (n.), but the signification of the second element is obscure.
ninth (adj.)youdaoicibaDictYouDict
c. 1300, modification (by influence of nine) of nigonðe, from Old English nigoða, nigend.
NiobeyoudaoicibaDictYouDict
in Greek mythology, a queen of Thebes, daughter of Tantalus, changed to a stone while weeping for her children (slain, after she boasted of them overmuch, by Artemis and Apollo); hence the name is used figuratively for bereavement and woe. The name is said to mean literally "snowy; snowy-bright."
niobium (n.)youdaoicibaDictYouDict
named by German scientist Heinrich Rose, who discovered it in 1844 in a mineral then called tantalum; so called because in Greek mythology Niobe was the daughter of Tantalus.
nip (n.2)youdaoicibaDictYouDict
"a pinch; a sharp bite," 1540s, from nip (v.). Meaning "a chill in the weather" is from 1610s, probably so called for its effect on vegetation. Nip and tuck "a close thing" is recorded from 1832, perhaps from sailing or tailoring.
nip (v.)youdaoicibaDictYouDict
"to pinch sharply; to bite suddenly," late 14c., related to Middle Low German nipen "to nip, to pinch," German nippen, Middle Dutch nipen "to pinch," Dutch nijpen, Old Norse hnippa "to prod," but the exact evolution of the stem is obscure. Related: Nipped; nipping. To nip (something) in the bud in the figurative sense is first recorded c. 1600.
nip (n.1)youdaoicibaDictYouDict
"small measure of spirits," 1796, shortening of nipperkin (1670s) "quantity of liquor of a half pint or less," possibly of Dutch or Low German origin (compare German Nipp "sip, taste") and related to nip (v.). Reinforced by nip (n.2) on notion of "fragment or bit pinched off" (c. 1600).
nipper (n.)youdaoicibaDictYouDict
"small boy," 1859, originally (1530s) a pickpocket who "pinched" other people's property; see nip (v.).
nipple (n.)youdaoicibaDictYouDict
1530s, nyppell, "teat, duct-laden extremity of a mammalian breast," alteration of neble (1520s), probably diminutive of neb "bill, beak, snout" (see neb), hence, literally "a small projection." In reference to an artificial device on an infant's bottle, from 1875. A 16c.-17c. slang term for a woman's nipples was cherrilets.
NipponeseyoudaoicibaDictYouDict
"Japanese," 1859, from Nippon, Japanese word for "Japan," from ni(chi) "the sun" + pon, hon "source," which is said to be from Chinese for "rising sun-place." Derisive slang shortening Nip attested from 1942.