v.1. To be the same, comparable, or in agreement: There's some kind of mistake—the numbers you wrote on these two forms don't match up. Match the pictures up—they're crooked.
2. To cause something to be the same, comparable, or in agreement: He matched up the edges of the books on the bookcase. Match the pictures up—they're crooked.
3. To form a pair or group from some set of people or things: I have to thank the dating service for matching us up. I matched up the socks.
4. match up with To be the same as, comparable with, or in agreement with something else: Each number on this list must match up with the numbers on the other list.
5. match up with To take something as a corresponding element or partner: The teacher asked each student to match up with one other student and form a double line.