sacrarium

noun

1. (historical)In Ancient Rome, a place where sacred objects were kept, either in a temple (the adytum) or in a house (holding the penates)
2. The area surrounding the altar of a Christian church; the sanctuary or piscina. Sometimes specifically a drain directly to the earth, perhaps including reference to a basin, for washing vessels from consecration.

   “The hay-trusser deposited his basket by the font, went up the nave till he reached the altar-rails, and opening the gate entered the sacrarium, where he seemed to feel a sense of the strangeness for a moment; then he knelt upon the footpace.”

   “2016, Martin Pousson, Black Sheep Boy, Los Angeles: Rare Bird Books, Part I, “Wanted Man,” The bathroom looked like a radiant sacristy, the sink a piscine, the drain a sacrarium.”

3. The complex sacrum of any bird.