sacrarium

noun3

1. •
   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 bathroom looked like a radiant sacristy, the sink a piscine, the drain a sacrarium. — 2016
2. •
   (historical) In Ancient Rome, a place where sacred objects were kept, either in a temple (the adytum) or in a house (holding the penates)
3. •
   The complex sacrum of any bird.