piscina

[piscina]
Latin: fish-pond or basin; also called a sacrarium, thalassicon, or fenestbella

The baptismal font, or the cistern into which the water flows after baptism. Also an excavation about two or three feet deep and one foot wide, covered with a stone slab, to receive the water from the washing of the priest’s hands and the water used for washing the palls, purifiers, and corporals; also the bread crumbs, cotton, etc., after the sacred unctions, and the ashes of sacred things no longer fit for use. It is generally constructed near the altar at the south wall of the sanctuary or in the sacristy. It is sometimes in the form of a perforated stone basin, or a small column or niche of stone or metal.