river vs Irrawaddy

river and Irrawaddy both are nouns.

Word	Noun	Adjective	Verb	Adverb
river	Yes	No	No	No
Irrawaddy	Yes	No	No	No

river (noun)	Irrawaddy (noun)
a large natural stream of water (larger than a creek)	the main river of Myanmar rising in the north and flowing south through the length of Burma to empty into the Andaman Sea