a bowl used for ablutions
A ceremony during the Eucharist at which the celebrant washes his or her hands. From the Latin "lavare," or "I shall wash."
A small bowl that is placed under the priest's hands. It will be used to collect water that is poured over the priest's hands prior to communion.
The washing of the celebrant's fingers after the Offertory at the Eucharist or at other times such as when oil or chrism is used or after the imposition of ashes on Ash Wednesday.
A lavabo is a device used to provide water. In ecclesiastical usage it is the basin in which the priest washes his hands after preparing the Altar before saying Mass. The room in which it is kept is the lavatory.