From Latin 'advocatus' (one called to aid) — 'vocare' (to call) also gave us 'voice,' 'invoke,' and 'vocation.'
A person who publicly supports or recommends a particular cause or policy; to publicly recommend or support.
From Latin advocātus (one called to aid, a legal counselor), past participle of advocāre (to call to one's aid, to summon), formed from ad- (to, toward) + vocāre (to call). The Latin verb vocāre derives from vox, vocis (voice, call) from PIE *wekʷ- (to speak, to call aloud). In Roman courts an advocātus was literally someone you had summoned to stand beside you — a legal friend