breeches buoy vs life ring

breeches buoy and life ring both are nouns.

Word	Noun	Adjective	Verb	Adverb
breeches buoy	Yes	No	No	No
life ring	Yes	No	No	No

As nouns, life ring is a hypernym of breeches buoy; that is, life ring is a word with a broader meaning than breeches buoy:

breeches buoy: a life buoy in the form of a ring with short breeches for support; used to transfer people from a ship
life ring: a life preserver in the form of a ring of buoyant material

Other hypernyms of breeches buoy include life belt, life buoy, lifesaver.

breeches buoy (noun)	life ring (noun)
a life buoy in the form of a ring with short breeches for support; used to transfer people from a ship	a life preserver in the form of a ring of buoyant material