catchment area vs river basin

catchment area and river basin both are nouns.

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

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

catchment area 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 area include basin, catchment basin, drainage area, drainage basin, watershed.

catchment area (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