prosthesis vs pegleg

prosthesis and pegleg both are nouns.

Word	Noun	Adjective	Verb	Adverb
prosthesis	Yes	No	No	No
pegleg	Yes	No	No	No

As nouns, pegleg is a hyponym of prosthesis; that is, pegleg is a word with a more specific, narrower meaning than prosthesis:

Other hyponyms of prosthesis include glass eye, implant, obturator, leg, peg, wooden leg, vascular conduit, vascular prosthesis.

prosthesis (noun)	pegleg (noun)
corrective consisting of a replacement for a part of the body	a prosthesis that replaces a missing leg