1. To stand in a row while waiting to receive or do something. We all lined up for ice cream. Why don't we go line up for our tickets now?

2. To stand in a line for a certain amount of time (while waiting to receive or do something). We lined up for nearly an hour to go on the new ride at the amusement park. I hate having to line up for more than five minutes when I do my grocery shopping.

3. To cause or direct someone or something to form or get into a line while waiting to receive or do something. In this usage, a noun or pronoun can be used before or after "up." Go line up the kids for their party favors. There were too many people crowding into the box office, so I asked security to line them up for a chance to buy tickets.