frame of reference vs reference system

frame of reference and reference system both are nouns.

Word	Noun	Adjective	Verb	Adverb
frame of reference	Yes	No	No	No
reference system	Yes	No	No	No

As nouns, frame of reference and reference system are synonyms defined as:

frame of reference and reference system: a system that uses coordinates to establish position

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

frame of reference (noun)	reference system (noun)
a system that uses coordinates to establish position	a system that uses coordinates to establish position
a system of assumptions and standards that sanction behavior and give it meaning