expiration (n.)

early 15c., expiracioun, "vapor, breath," from Latin expirationem/exspirationem (nominative expiratio/exspiratio) "a breathing out, exhalation," noun of action from past-participle stem of expirare/exspirare "breathe out; breathe one's last" (see expire). Meaning "termination, end, close" is from 1560s.