1. a shop, business establishment, or part thereof, in which terms and conditions of employment for all employees are fixed by agreement between the employer and a labor union.
2. a shop, business, etc., in which membership in a union is made a condition of employment, but in which the employer may hire nonunion workers provided that they become members after a stated period, usually 30 days. Cf. nonunion shop.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.