catchment basin vs river basin

catchment basin and river basin both are nouns.

Word	Noun	Adjective	Verb	Adverb
catchment basin	Yes	No	No	No
river basin	Yes	No	No	No

As nouns, catchment basin and river basin are synonyms defined as:

catchment basin and river basin: the entire geographical area drained by a river and its tributaries; an area characterized by all runoff being conveyed to the same outlet

Other synonyms of catchment basin include basin, catchment area, drainage area, drainage basin, watershed.

catchment basin (noun)	river basin (noun)
the entire geographical area drained by a river and its tributaries; an area characterized by all runoff being conveyed to the same outlet	the entire geographical area drained by a river and its tributaries; an area characterized by all runoff being conveyed to the same outlet