prep., adv., & adj.
prep. 1 expressing inclusion or position within limits of space, time, circumstance, etc. (in England; in bed; in the rain). 2 during the time of (in the night; in 1989). 3 within the time of (will be back in two hours). 4 a with respect to (blind in one eye; good in parts). b as a kind of (the latest thing in luxury). 5 as a proportionate part of (one in three failed; a gradient of one in six). 6 with the form or arrangement of (packed in tens; falling in folds). 7 as a member of (in the army). 8 concerned with (is in politics). 9 as or regarding the content of (there is something in what you say). 10 within the ability of (does he have it in him?). 11 having the condition of; affected by (in bad health; in danger). 12 having as a purpose (in search of; in reply to). 13 by means of or using as material (drawn in pencil; modelled in bronze). 14 a using as the language of expression (written in French). b (of music) having as its key (symphony in C). 15 (of a word) having as a beginning or ending (words in un-). 16 wearing as dress (in blue; in a suit). 17 with the identity of (found a friend in Mary). 18 (of an animal) pregnant with (in calf). 19 into (with a verb of motion or change: put it in the box; cut it in two). 20 introducing an indirect object after a verb (believe in; engage in; share in). 21 forming adverbial phrases (in any case; in reality; in short).
adv. expressing position within limits, or motion to such a position: 1 into a room, house, etc. (come in). 2 at home, in one's office, etc. (is not in). 3 so as to be enclosed or confined (locked in). 4 in a publication (is the advertisement in?). 5 in or to the inward side (rub it in). 6 a in fashion, season, or office (long skirts are in; strawberries are not yet in). b elected (the Democrat got in). 7 exerting favourable action or influence (their luck was in). 8 Cricket (of a player or side) batting. 9 (of transport) at the platform etc. (the train is in). 10 (of a season, harvest, order, etc.) having arrived or been received. 11 Brit. (of a fire) continuing to burn. 12 denoting effective action (join in). 13 (of the tide) at the highest point. 14 (in comb.) colloq. denoting prolonged or concerted action, esp. by large numbers (sit-in; teach-in).
adj. 1 internal; living in; inside (in-patient). 2 fashionable, esoteric (the in thing to do). 3 confined to or shared by a group of people (in-joke). in all see ALL. in at present at; contributing to (in at the kill). in between see BETWEEN adv. in-between attrib.adj. colloq. intermediate (at an in-between stage). in for 1 about to undergo (esp. something unpleasant). 2 competing in or for. 3 involved in; committed to. in on sharing in; privy to (a secret etc.). ins and outs (often foll. by of) all the details (of a procedure etc.). in so far as see FAR. in that because; in so far as. in with on good terms with.
[ OE in, inn, orig. as adv. with verbs of motion ]