octet vs digit

octet and digit both are nouns.

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

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

Other hypernyms of octet include figure.

octet (noun)	digit (noun)
a musical composition written for eight performers	a finger or toe in human beings or corresponding body part in other vertebrates
eight people considered as a unit	one of the elements that collectively form a system of numeration
a set of eight similar things considered as a unit	the length of breadth of a finger used as a linear measure
eight performers or singers who perform together
the cardinal number that is the sum of seven and one