waterway vs watercourse

waterway and watercourse both are nouns.

Word	Noun	Adjective	Verb	Adverb
waterway	Yes	No	No	No
watercourse	Yes	No	No	No

As nouns, waterway and watercourse are synonyms defined as:

waterway (noun)	watercourse (noun)
a conduit through which water flows	a conduit through which water flows
a navigable body of water	a natural body of running water flowing on or under the earth
	natural or artificial channel through which water flows