buoy vs point of reference

buoy and point of reference both are nouns.

Word	Noun	Adjective	Verb	Adverb
buoy	Yes	No	Yes	No
point of reference	Yes	No	No	No

As nouns, point of reference is a hypernym of buoy; that is, point of reference is a word with a broader meaning than buoy:

buoy: a float attached by rope to the seabed to mark channels in a harbor or underwater hazards; typically brightly-coloured
point of reference: an indicator that orients you generally

Other hypernyms of buoy include reference, reference point.

buoy (noun)	point of reference (noun)
a float attached by rope to the seabed to mark channels in a harbor or underwater hazards; typically brightly-coloured	an indicator that orients you generally