Old English in (prep.) "in, into, upon, on, at, among; about, during;" inne (adv.) "within, inside," from Proto-Germanic *in (cf. Old Frisian, Dutch, German, Gothic in, Old Norse i), from PIE *en "in" (cf. 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.
suffix attached to a verb, first attested 1960 with sit-in (which probably was influenced by sit-down strike); used first of protests, extended c.1965 to any gathering.
chemical suffix, usually indicating a neutral substance, antibiotic, vitamin, or hormone; see -ine (2).
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)).
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- (cf. Old English onliehtan "to enlighten"), and some verbs survived into Middle English (cf. 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."
The symbol for the element indium.
in- 1 or il- or im- or ir-
in- 2 or il- or im- or ir-
In; into; within: intubation.
Neutral chemical compound: inulin.
Variant of -ine2.
The symbol for indium.
A soft, malleable, silvery-white metallic element that occurs mainly in ores of zinc and lead. It is used in the manufacture of semiconductors, in bearings for aircraft engines, and as a plating over silver in mirrors. Atomic number 49; atomic weight 114.82; melting point 156.61°C; boiling point 2,080°C; specific gravity 7.31; valence 1, 2, 3. See Periodic Table.
Abbreviation of inch
get in, have it in for someone
A communal occasion where one does what is indicated: be-in/ lie-in/ love-in/ pray-in (1960s+)