To be in

In In, adv. 1. Not out; within; inside. In, the preposition, becomes an adverb by omission of its object, leaving it as the representative of an adverbial phrase, the context indicating what the omitted object is; as, he takes in the situation (i. e., he comprehends it in his mind); the Republicans were in (i. e., in office); in at one ear and out at the other (i. e., in or into the head); his side was in (i. e., in the turn at the bat); he came in (i. e., into the house). [1913 Webster]

Their vacation . . . falls in so pat with ours. --Lamb. [1913 Webster]

Note: The sails of a vessel are said, in nautical language, to be in when they are furled, or when stowed. In certain cases in has an adjectival sense; as, the in train (i. e., the incoming train); compare up grade, down grade, undertow, afterthought, etc. [1913 Webster]

2. (Law) With privilege or possession; -- used to denote a holding, possession, or seisin; as, in by descent; in by purchase; in of the seisin of her husband. --Burrill. [1913 Webster]

{In and in breeding}. See under {Breeding}.

{In and out} (Naut.), through and through; -- said of a through bolt in a ship's side. --Knight.

{To be in}, to be at home; as, Mrs. A. is in.

{To come in}. See under {Come}. [1913 Webster]