fender vs safety device

fender and safety device both are nouns.

Word	Noun	Adjective	Verb	Adverb
fender	Yes	No	No	No
safety device	Yes	No	No	No

As nouns, safety device is a hypernym of fender; that is, safety device is a word with a broader meaning than fender:

Other hypernyms of fender include guard, safety.

fender (noun)	safety device (noun)
a cushion-like device that reduces shock due to an impact	a device designed to prevent injury or accidents
a barrier that surrounds the wheels of a vehicle to block splashing water or mud
a low metal guard to confine falling coals to a hearth
an inclined metal frame at the front of a locomotive to clear the track