> Etymology: < post-classical Latin plenarius fully attended, complete (late 4th cent. in Augustine in plenarium concilium ) < classical Latin plēnus full (see pleni- comb. form) + -ārius -ary suffix1. Compare Old Occitan plenari , Catalan plenari (15th cent.), Spanish plenario (c1255 or earlier), Portuguese plenario (15th cent.), Italian plenario (13th cent.). Compare also plenar adj. and the Romance parallels cited at that entry.
With plenary indulgence at sense A. 1 compare French indulgeance pleniere (1636), Spanish indulgencia plenaria (a1450 or earlier), Italian indulgenza plenaria (1…