n. Eccles., in the Roman Catholic Church, and in many Anglican churches, the ritual act of washing the celebrant's hands after the offertory and before entering upon the more solemn part of the eucharistic service: so called from the priest's reciting at the time the last part of the 26th psalm, beginning with the sixth verse, “I will wash my hands in innocency,” in Latin, “Lavabo manus meas in innocentia.” In the Greek Church this takes place in the prothesis, before vesting.n. In many monasteries of the middle ages, a large stone basin from which the water issued by a number of small orifices around the edge, for the convenient performance of ablutions before religious exercises or meals.n. Hence A convenience of similar object and arrangement in some modern schools or institutions; a lavatory.n. The psalm in the mass service which the priest recites at the washing of his hands.