la·va·bo 
(lə-vābō, -vä-)
(lə-vābō, -vä-)n. pl. la·va·boes
1. often Lavabo The ceremonial washing of the hands and recitation from the Psalms by the celebrant before the Eucharist in the Roman Catholic and Anglican churches.
2. A washbowl that is attached to a wall and filled from a water tank fastened above.
[From Latin lavābō, I shall wash (opening word of the recited portion of Psalm 26), first person future tense of lavāre, to wash; see leu(ə)- in the Appendix of Indo-European roots.]