fetlock vs appendage

fetlock and appendage both are nouns.

Word	Noun	Adjective	Verb	Adverb
fetlock	Yes	No	No	No
appendage	Yes	No	No	No

As nouns, appendage is a hypernym of fetlock; that is, appendage is a word with a broader meaning than fetlock:

fetlock: projection behind and above a horse's hoof
appendage: a natural prolongation or projection from a part of an organism either animal or plant

Other hypernyms of fetlock include outgrowth, process.

fetlock (noun)	appendage (noun)
projection behind and above a horse's hoof	a part that is joined to something larger
the joint between the cannon bone and the pastern	an external body part that projects from the body
	a natural prolongation or projection from a part of an organism either animal or plant