mid-14c., "one whose profession is to plead cases in a court of justice," a technical term from Roman law, from Old French avocat "barrister, advocate, spokesman," from Latin advocatus "one called to aid; a pleader, advocate," noun use of past participle of advocare "to call" (as witness or advisor) from ad- "to" (see ad-) + vocare "to call," related to vocem (see voice (n.)). Also in Middle English as "one who intercedes for another," and "protector, champion, patron." Feminine forms advocatess, advocatrice were in use in 15c.
1640s, from advocate (n.). Related: Advocated; advocating; advocation.
(Gr. parakletos), one who pleads another's cause, who helps another by defending or comforting him. It is a name given by Christ three times to the Holy Ghost (John 14:16; 15:26; 16:7, where the Greek word is rendered "Comforter," q.v.). It is applied to Christ in 1 John 2:1, where the same Greek word is rendered "Advocate," the rendering which it should have in all the places where it occurs. Tertullus "the orator" (Acts 24:1) was a Roman advocate whom the Jews employed to accuse Paul before Felix.