galley slave

noun2

1. •
   (historical) A slave who rows in a galley (type of ship).

   • "What are gurapas?" asked Don Quixote. "Gurapas are galleys," responded the galley slave. — 1605
2. •
   (slang, no longer used) A typesetter (person who arranged type in a galley for printing).

   • The "galley slaves" in those days were the genuine article, and by the "chains that bound them" were no doubt the original members of the union. — 1905