Round up Definition 1 of 4Pro Tip 1/3Active Search Implies actively finding, not just waiting for things or people to gather. We rounded up all the chairs for the meeting. Pro Tip 2/3Quick Assembly Often suggests urgency or promptness in gathering people or things. Quick, round up the volunteers; we're starting now! Pro Tip 3/3Temporary Grouping Used for temporary or changing groups, not fixed organizations. Let's round up some folks for a pickup basketball game.