- posterior (adj.)
- 1530s, "later," from Latin posterior "after, later, behind," comparative of posterus "coming after, subsequent," from post "after" (see post-). Meaning "situated behind" is from 1630s.
- posterior (n.)
- "buttocks," euphemistic, 1610s, from posterior (adj.). Earlier it meant "those who come after, posterity" (1530s). Compare Lithuanian pasturas "the last, the hindmost," from pas "at, by."
