c.1200, tumbe, early 14c. tomb, from Anglo-French tumbe and directly from Old French tombe "tomb, monument, tombstone" (12c.), from Late Latin tumba (also source of Italian tomba, Spanish tumba), from Greek tymbos "burial mound, cairn," generally "grave, tomb," perhaps from PIE root *teue- (2) "to swell" (see thigh). The final -b began to be silent about the time of the spelling shift (compare lamb, dumb). Modern French tombeau is from Vulgar Latin diminutive *tumbellus. The Tombs, slang for "New York City prison" is recorded from 1840.