Labor aristocracy or labour aristocracy (also aristocracy of labor) has at least four meanings: (1) as a term with Marxist theoretical underpinnings; (2) as a specific type of trade unionism; (3) as a shorthand description by revolutionary industrial unions (such as the Industrial Workers of the World) for the bureaucracy of craft-based business unionism; and (4) in the 19th and early 20th centuries was also a phrase used to define better-off members of the working class (as used for example by Jack London in The People of the Abyss).