What is the meaning of Adytum?

The innermost sanctuary or shrine in a temple, from where oracles were given.

A private chamber; a sanctum.

inner shrine, sanctuary, Holy of Holies: (the innermost or most secret part of a temple or other sacred place; the sanctuary, which none but priests could enter, and from which oracles were delivered)

a secret place or chamber

a grave, tomb, or mausoleum

the inmost recesses

accusative singular of adytus

Source: wiktionary.org