evacuate (v.)
1520s, from Latin evacuatus, past participle of evacuare "to empty, make void, nullify," used by Pliny in reference to the bowels, used figuratively in Late Latin for "clear out," from ex- "out" (see ex-) + vacuus "empty" (see vacuum).

Earliest sense in English is medical. Meaning "remove inhabitants to safer ground" is from 1934. Replaced Middle English evacuen (c.1400). Related: Evacuated; evacuating.