Teammate (noun)

1. A fellow member of a team, especially in a sports team.
2. Someone who works together with another person or group of people.

Origin:

From team + mate.

Examples:

1. He was a valuable teammate on the basketball team.
2. She was very supportive of her teammates.
3. He was a great leader and a good teammate.
4. I was fortunate to have such a great group of teammates.
5. He was happy to be playing with such a talented group of teammates.