YELLOW-DOG CONTRACT: An agreement signed by workers before they are hired, stipulating that they would not join a union after they are hired. This contract was commonly used by firms in the late 1800s and early 1900s to limit labor union membership and thus to prevent unions from exerting control over the labor market. Yellow-dog contracts were outlawed by the Norris-LaGuardia Act in 1932. See also | labor union | Norris-LaGuardia Act | open shop | union shop | closed shop | right to work | Taft-Hartley Act | factor market | monopoly | National Labor Relations Act |