complementum

complēmentum, i, n. [compleo],

that which fills up or completes , a complement (rare; only fig.): numerorum (inania quaedam verba), * Cic. Or. 69, 230: omnium accusationum, that gives them their full weight , Tac. A. 3, 38: accusationis, Cod. Th. 9, 24, 3.