What is another word for closed shop?
Pronunciation: [klˈə͡ʊzd ʃˈɒp] (IPA) 
The term "closed shop" refers to an organization or workplace that only hires union members, while "union shop" refers to a workplace where employees are required to join the union after a set period of employment. Another synonym for "closed shop" is "union security agreement," which is a contractual arrangement between an employer and union that establishes the conditions for union membership. Additionally, "pre-hire agreement" is used to describe a situation where a union and employer agree to the terms of a closed shop prior to hiring any workers. Ultimately, all of these terms refer to the practice of requiring union membership as a condition of employment in a particular workplace.
