Yours, Etc.: Origins and Uses of 8 Sign-Offs
"one who rules during the minority or absence of a sovereign," c.1400, from the adjective (now archaic, attested in English late 14c.), from Old French regent and directly from Medieval Latin regentem (nominative regens), from Latin regens "ruler, governor," noun use of present participle of regere "to rule, direct" (see regal). Senses of "university faculty member" is attested from mid-15c., originally Scottish.