Answer: omphalos

AnswerCrossword Clue
OMPHALOSNavel
OMPHALOSBelly button
omphalos(Greek) a central point, a navel
omphalosthe central point.
omphalosA rounded stone (esp. that at Delphi) representing the navel of the earth in ancient Greek mythology
omphalosThe center or hub of something