Source : Webster's Revised Unabridged Dictionary (1913)

Omphalos \Om"pha*los\, n. [L., fr. Gr. ?.] (Anat.)
   The navel.

Source : WordNet®

omphalos
     n : scar where the umbilical cord was attached [syn: {navel}, {umbilicus},
          {bellybutton}, {omphalus}]