Etymology: Middle English, from Old English; akin to Old High German in in, Latin in, Greek en
Date: before 12th century
a. — used as a function word to indicate inclusion, location, or position within limits <in the lake> <wounded in the leg> <in the summer> b. into 1 <went in the house> 2. — used as a function word to indicate means, medium, or instrumentality <written in pencil> <bound in leather> 3. a. — used as a function word to indicate limitation, qualification, or circumstance <alike in some respects> <left in a hurry> b. into 2a <broke in pieces> 4. — used as a function word to indicate purpose <said in reply> 5. — used as a function word to indicate the larger member of a ratio <one in six is eligible> II. adverb Date: before 12th century 1. a. (1) to or toward the inside especially of a house or other building <come in> (2) to or toward some destination or particular place <flew in on the first plane> (3) at close quarters ; near <play close in> b. so as to incorporate <mix in the flour> — often used in combination <built-in bookcases> c. to or at an appropriate place <fit a piece in> 2. a. within a particular place; especially within the customary place of residence or business <the doctor is in> b. in the position of participant, insider, or officeholder — often used with on <in on the joke> c. (1) on good terms (2) in a specified relation <in bad with the boss> (3) in a position of assured or definitive success d. in vogue or season e. of an oil well in production f. in one's presence, possession, or control <after the crops are in> g. from a condition of indistinguishability to one of clarity <fade in> III. adjective Date: 1599 1. a. that is located inside or within <the in part> b. that is in position, operation, or power <the in party> c. inside 2 2. that is directed or bound inward ; incoming <the in train> 3. a. extremely fashionable <the in thing to do> b. keenly aware of and responsive to what is new and fashionable <the in crowd> IV. noun Date: 1764 1. one who is in office or power or on the inside <a matter of ins versus outs> 2. influence, pull <enjoyed some sort of in with the commandant — Henriette Roosenburg> V. abbreviation 1. inch 2. inlet
New Collegiate Dictionary. 2001.