Ob vs Ob River

Ob and Ob River both are nouns.

Word	Noun	Adjective	Verb	Adverb
Ob	Yes	No	No	No
Ob River	Yes	No	No	No

As nouns, Ob and Ob River are synonyms defined as:

Ob and Ob River: a major river of western Siberia; flows generally northward and westward to the Gulf of Ob and the Kara Sea

Ob (noun)	Ob River (noun)
a major river of western Siberia; flows generally northward and westward to the Gulf of Ob and the Kara Sea	a major river of western Siberia; flows generally northward and westward to the Gulf of Ob and the Kara Sea