If you're part of a frisbee team, you're part of a group of people who cooperate to throw a plastic disc around. It's neat.
Two or more of people working together on a single task can be called a team, whether that's an informal team or a professional one. The two horses that pull your carriage are a team, and the guys you play soccer with on Saturday mornings are also a team. Team can also be a verb, meaning "to join forces." If you want to beautify your town, team up with local people to paint a mural for the community.