one person; one member
Used when counting or referring to a single person as a member of a group, team, or organization. Often appears in contexts like 一員として (as a member).
彼はチームの一員として活躍した。
He played an active role as a member of the team.
家族の一員が増えた。
Our family gained one more member.
He competed in the tournament as a member of the team.
She became a member of that research team.
The new employee was finally accepted as a member of the workplace.