late 15c., from Old French revocable or directly from Latin revocabilis "that may be revoked," from revocare (see revoke). Alternative revokable attested from 1580s.[revocable etymology, revocable origin, 英语词源]
mid-14c., from Old French revoquer (13c.), from Latin revocare "rescind, call back," from re- "back" (see re-) + vocare "to call" (see voice (n.)). Related: Revoked; revoking.