c.1300, from L. latrina,
contraction of lavatrina
"washbasin, washroom," from lavatus,
pp. of lavare
"to wash" (see lave
) + -trina,
suffix denoting "workplace." Its reappearance in 1640s is probably a re-borrowing from Fr.; esp. of a 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.