The term "union leader" refers to an individual who holds a position of authority within a labor union. A labor union is an organization that represents workers in negotiations with employers concerning wages, hours, and other conditions of employment. Union leaders are elected by the members of their respective unions and play a critical role in advocating for worker's rights, negotiating contracts, and leading collective bargaining efforts. They also work to improve working conditions, provide support and resources to union members, and represent the interests of workers at the local, state or national level.