Pontos vs Pontus

Pontos and Pontus both are nouns.

Word	Noun	Adjective	Verb	Adverb
Pontos	Yes	No	No	No
Pontus	Yes	No	No	No

As nouns, Pontos and Pontus are synonyms defined as:

Pontos and Pontus: (Greek mythology) ancient personification of the sea; father of Nereus

Pontos (noun)	Pontus (noun)
(Greek mythology) ancient personification of the sea; father of Nereus	an ancient region of northern Asia Minor on the Black Sea; it reached its height under Mithridates VI but was later incorporated into the Roman Empire
	(Greek mythology) ancient personification of the sea; father of Nereus