appendage vs digit

appendage and digit both are nouns.

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

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

appendage: an external body part that projects from the body
digit: a finger or toe in human beings or corresponding body part in other vertebrates

Other hyponyms of appendage include chelicera, mouthpart, fang, chela, claw, nipper, pincer, parapodium, fin, pleopod, swimmeret, limb, dactyl.

appendage (noun)	digit (noun)
a part that is joined to something larger	a finger or toe in human beings or corresponding body part in other vertebrates
an external body part that projects from the body	one of the elements that collectively form a system of numeration
a natural prolongation or projection from a part of an organism either animal or plant	the length of breadth of a finger used as a linear measure