line up (Verb) — Form a line. ex. "The buildings all line up neatly"
line up (Verb) — Get something or somebody for a specific purpose.
line up (Verb) — Form a queue, form a line, stand in line. ex. "Customers lined up in front of the store"
line up (Verb) — Place in a line or arrange so as to be parallel or straight. ex. "line up the car with the curb"
line up (Verb) — Arrange in ranks. ex. "line up troops"
line up (Verb) — (football) take one's position before a kick-off.
line up (Noun) — A line of persons arranged by police for inspection or identification.
line up (Noun) — (baseball) a list of batters in the order in which they will bat. ex. "the managers presented their lineups to the umpire at home plate"