integer vs digit

integer and digit both are nouns.

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

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

integer (noun)	digit (noun)
any of the natural numbers (positive or negative) or zero	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