umbilicus vs omphalos

umbilicus and omphalos both are nouns.

Word	Noun	Adjective	Verb	Adverb
umbilicus	Yes	No	No	No
omphalos	Yes	No	No	No

As nouns, umbilicus and omphalos are synonyms defined as:

Other synonyms of umbilicus include belly button, bellybutton, navel, omphalus.

umbilicus (noun)	omphalos (noun)
a scar where the umbilical cord was attached	a scar where the umbilical cord was attached