英语词源字典 - 在线词源网站

in [in 词源字典]: Old English in (prep.) "in, into, upon, on, at, among; about, during;" inne (adv.) "within, inside," from Proto-Germanic *in (cognates: Old Frisian, Dutch, German, Gothic in, Old Norse i), from PIE *en "in" (cognates: Greek en, Latin in "in, into," Old Irish in, Welsh yn-, Old Church Slavonic on-). As an adjective from 1590s.

The forms merged in Middle English. Modern sense distinction between in and on is from later Middle English. Sense of "holding power" (the in party) first recorded c. 1600; that of "exclusive" (the in-crowd, an in-joke) is from 1907 (in-group); that of "stylish, fashionable" (the in thing) is from 1960. The noun sense of "influence, access" (have an in with) first recorded 1929 in American English. In-and-out "copulation" is attested from 1610s.[in etymology, in origin, 英语词源]
in absentia: Latin, literally "in (his/her/their) absence" (see absence).
in extremis: "at the point of death," Latin, literally "in the farthest reaches."
in like Flynn: 1940s slang, said to have originated in the U.S. military, perhaps from alleged sexual exploits of Hollywood actor Errol Flynn.
in loco parentis: Latin, literally "in the place of a parent" (see parent).
in medias res: Latin, literally "in the midst of things" (see medium).
in memoriam: Latin, literally "in memory of" (see memory).
in situ: Latin, literally "in its (original) place or position" (see situate (v.)).
in toto: Latin, "as a whole, completely" (see total).
in utero: Latin, literally "in the uterus" (see uterus).
in vitro: Latin; "in a test tube, culture dish, etc.;" literally "in glass" (see vitreous).
in vivo: Latin; "within a living organism" (see viva).
in't: archaic; 17c. as short for in it.
in't: archaic or poetic contraction of in it.
in- (1): prefix meaning "not, opposite of, without" (also im-, il-, ir- by assimilation of -n- with following consonant), from Latin in- "not," cognate with Greek an-, Old English un-, from PIE *ne "not" (see un- (1)).
in- (2): element meaning "into, in, on, upon" (also im-, il-, ir- by assimilation of -n- with following consonant), from Latin in- "in" (see in). In Old French this often became en-, which usually was respelled in English to conform with Latin, but not always, which accounts for pairs like enquire/inquire. There was a native form, which in West Saxon usually appeared as on- (as in Old English onliehtan "to enlighten"), and some verbs survived into Middle English (such as inwrite "to inscribe"), but all now seem to be extinct. Not related to in- (1) "not," which also was a common prefix in Latin: to the Romans impressus could mean "pressed" or "unpressed."
in-fighting (n.): 1812, from pugilism, the practice of getting at close quarters with an opponent; see in + fighting. Old English infiht (n.) meant "brawl within a house or between members of a household."
in-joke (n.): 1964, from in + joke.
in-law (n.): 1894, "anyone of a relationship not natural," abstracted from father-in-law, etc.
The position of the 'in-laws' (a happy phrase which is attributed ... to her Majesty, than whom no one can be better acquainted with the article) is often not very apt to promote happiness. ["Blackwood's Magazine," 1894]
The earliest recorded use of the phrase is in brother-in-law (13c.); the law is Canon Law, which defines degrees of relationship within which marriage is prohibited.
in-migration (n.): 1942, in reference to movement within the same country, from in + migration.