Webster's Revised Unabridged Dictionary · 1913

Adytum

Adytum ({not transcribed}) , noun

[Latin, from Greek {not transcribed}, n., from {not transcribed}, a., not to be entered; 'a priv. + {not transcribed} to enter.]

The innermost sanctuary or shrine in ancient temples, whence oracles were given. Hence: A private chamber; a sanctum.