Omphalos n. : The navel.

Example:
Is there a link between the Omphalos of Egyptian mythology - and The Ark of the covenant?

Taxonomy
Omphalos, stone, Delphi, navel, Jerusalem, free encyclopedia, the Foundation stone, in Jerusalem, Jewish tradition, Buck Mulligan, Greek Religion, Zeus, temple, gods, the Church of the Holy Sepulchre, tradition, oracle, Greek mythology.

Defination from the web:
omphalos means "navel" (compare the name of Queen Omphale) ... Omphalos stones used to denote this point were erected in several areas surrounding the Mediterranean Sea; the most famous of those was at the oracle in Delphi. ...