A closed shop is a union term. It was created in the 1930s and signed into law by President Roosevelt. The union term "closed shop" refers to an agreement made between the employer and employee that during the term of employment, the employee will not work for another job that is non union and the company will not hire non-union workers.

This means that only union workers will be hired to perform certain jobs and tasks. If this contract is broken during the term of employment, some union workers may walk off the job before working along the side of a non-union worker. A man may join and become part of the union to gain employment but once he is union, he may not work for another job unless it is also within the union.