wooden leg vs prosthetic device

wooden leg and prosthetic device both are nouns.

Word	Noun	Adjective	Verb	Adverb
wooden leg	Yes	No	No	No
prosthetic device	Yes	No	No	No

As nouns, prosthetic device is a hypernym of wooden leg; that is, prosthetic device is a word with a broader meaning than wooden leg:

wooden leg: a prosthesis that replaces a missing leg
prosthetic device: corrective consisting of a replacement for a part of the body

Other hypernyms of wooden leg include prosthesis.

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