latrine n.

c. 1300, laterin "a privy," probably from Latin latrina, latrinum, a contraction of lavatrina "washbasin, washroom," from lavatus, past participle of lavare "to wash" (from PIE root *leue- "to wash") + -trina, suffix denoting "workplace." The word's reappearance in 1640s probably is a re-borrowing from French. In modern use, especially of a public privy of a camp, barracks, college, hospital, etc. Latrine rumor "baseless gossip" (of the kind that spreads in conversations in latrines) is military slang, first recorded 1918.