reference system vs coordinate system

reference system and coordinate system both are nouns.

Word	Noun	Adjective	Verb	Adverb
reference system	Yes	No	No	No
coordinate system	Yes	No	No	No

As nouns, reference system and coordinate system are synonyms defined as:

reference system and coordinate system: a system that uses coordinates to establish position

Other synonyms of reference system include frame of reference, reference frame.

reference system (noun)	coordinate system (noun)
a system that uses coordinates to establish position	a system that uses coordinates to establish position