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).