Lewis & Short

ădytum, i, n., = ἄδυτον (not to be entered), the innermost part of a temple, the sanctuary, which none but priests could enter, and from which oracles were delivered.

  1. I. Lit.: in occultis ac remotis templi, quae Graeci ἄδυτα appellant, Caes. B. C. 3, 105: aeternumque adytis effert penetralibus ignem, Verg. A. 2, 297: isque adytis haec tristia dicta reportat, id. ib. 2, 115; 6, 98; Hor. C. 1, 16, 5.
    In gen., a secret place, chamber; of the dead, a grave, tomb, in Verg. A. 5, 84, and Juv. 13, 205: descriptionem cubiculorum in adytis, chambers in secret places, i. e. inner chambers, Vulg. 1 Par. 28, 11.
  2. II. Fig.: ex adyto tamquam cordis responsa dedere, the inmost recesses, * Lucr. 1, 737.
    Note: In Attius also masc. adytus, ūs: adytus augura, in Non. 488, 4 (Trag. Rel. p. 217 Rib.).