lavabo

noun

1. A ritual involving the washing of one's hands at a church's offertory before handling the Eucharist.
2. The small towel used to dry the priest's hands following the ritual.

   “These small liturgical towels got […] the name of Lavabo cloths or Lavaboes.”

3. A washbasin, particularly (Christianity) the one in a church used in the ritual.

   “[…] the […] pontiff, as he […] moved his hands […] at the Lavabo, or at the various benedictions […]”

4. A trough used for washing at some medieval monasteries.
5. (euphemistic, humorous)A lavatory: a room used for urination and defecation.

   “Mr. Pond fussed out and she heard the door of the little lavabo in the passage open with a loud creak.”