A Sacrarium

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. Piscina - Wikipedia
3. (anatomy) The complex sacrum of any bird.