Other forms: proles
A prole is a worker, or a member of the blue-collar working class. Someone who's employed at a mill or a factory is considered a prole.
Prole is short for proletariat, the collective name for workers that's especially common in (and was popularized by) Marxist economics. The word comes from the Latin proletarius, "citizen of the lowest class," used in ancient Rome to describe the group of people who didn't own property and whose only contribution to society was having children. It comes from proles, or "offspring."