hexadecimal digit vs digit

hexadecimal digit and digit both are nouns.

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

As nouns, digit is a hypernym of hexadecimal digit; that is, digit is a word with a broader meaning than hexadecimal digit:

Other hypernyms of hexadecimal digit include figure.

hexadecimal digit (noun)	digit (noun)
a digit from 0 to 15 in hexadecimal notation	a finger or toe in human beings or corresponding body part in other vertebrates
	one of the elements that collectively form a system of numeration
	the length of breadth of a finger used as a linear measure