Omphalos of Delphi in the context of "Mount Parnassus"

Delphi (/ˈdɛlfaɪ, ˈdɛlfi/; Greek: Δελφοί [ðelˈfi]), in legend previously called Pytho (Πυθώ), was an ancient sacred precinct in central Greece. It was the seat of Pythia, the major oracle who was consulted about important decisions throughout the ancient classical world. The ancient Greeks considered the centre of the world to be in Delphi, marked by the stone monument known as the Omphalos of Delphi. The term omphalos was the Greek word for "navel".

According to the Suda, Delphi took its name from the Delphyne, the she-serpent (drakaina) who lived there and was killed by the god Apollo (in other accounts the serpent was the male serpent (drakon) Python).

A baetyl (/ˈbiːtɪl/; also betyl), literally "house of god", is a sacred stone (sometimes believed to be a meteorite) that was venerated and thought to house a god or deity. The most famous example is the Omphalos stored in the Temple of Apollo at the Greek town of Delphi.

The term baetyl was used in ancient Near Eastern sources, in the form of "beth-el", as well as in Greek and Roman sources, as a baitylos. In the former, the term was used to refer to the names of gods or places. Examples include Bethel, a location described in the Hebrew Bible, and the deity Bethel, who was mentioned in texts like Esarhaddon's Treaty with Ba'al of Tyre and the Elephantine papyri. In the latter, the word was used to describe a round stone that had fallen from the sky (i.e. a meteorite).