1. To constitute a group or team of four people or things. The drummer, bassist, guitar player and singer make up a foursome of some of the most talented musicians in the industry.

2. To bring four people or things together into a group or team. We need to make up a foursome if we want to enter a team into the tournament. Most of the wedding guests are going to be couples, so it should be easy enough to make up foursomes for the reception dinner.