The term AFL stands for the American Federation of Labor, which is a labor UNION founded in 1886. It was one of the first federations of labor unions in the United States and was led by Samuel Gompers until his death in 1924. The CIO stands for the Congress of Industrial Organizations, which was a federation of labor unions that split from the AFL in 1935. The CIO was led by John L. Lewis until his retirement in 1940. Both the AFL and the CIO were instrumental in the development of labor rights in the United States.