Adyton

The adyton was frequently a small area at the farthest end of the cella from the entrance; at Delphi it measured just 9 by 12 feet (2.7 by 3.7 m).

Adyta were found frequently associated with temples of Apollo, as at Didyma, Bassae, Clarus, Delos, and Delphi, although they were also said to have been natural phenomena (see the story of Nyx).

Those sites often had been dedicated to deities whose worship preceded that of Apollo and may go back to prehistoric eras, such as Delphi, but who were supplanted by the time of Classical Greek culture.

[2] The term is sometimes extended to similar spaces in other cultural contexts, as in Egyptian temples or the Western mystery school, Builders of the Adytum.

By the early 19th century, the term acquired a figurative meaning, referring to the innermost parts of any structure or of the human psyche.

Location of the adyton within a temple
The adyton in the Temple of Apollo in Didyma