union shop

noun
  1. : a unionized business in which the employer by agreement is free to hire nonmembers as well as members of the union but union membership within a specified time (as 30 days) is a condition of continued employment — compare agency shop, closed shop, open shop

    Note: State law determines whether a collective bargaining agreement can have a clause creating a union shop. Many states having right-to-work laws bar union shop agreements.