in line (Adjective) — Being next in a line of succession. ex. "he was in line for the presidency"
in line (Adjective) — Awaiting something; especially something due. ex. "people were in line at the checkout counter" ex. "she was in line for promotion"
in line (Noun) — (computing) one of a set of small on-off switches mounted in computer hardware; used in place of jumpers to configure the machine for a user.
in line (Adverb) — One behind another in a line or queue. ex. "they waited in line for the tickets"