combining form vs bound form

combining form and bound form both are nouns.

Word	Noun	Adjective	Verb	Adverb
combining form	Yes	No	No	No
bound form	Yes	No	No	No

As nouns, bound form is a hypernym of combining form; that is, bound form is a word with a broader meaning than combining form:

combining form: a bound form used only in compounds
bound form: a morpheme that occurs only as part of a larger construction; eg an -s at the end of plural nouns

Other hypernyms of combining form include bound morpheme.

combining form (noun)	bound form (noun)
a bound form used only in compounds	a morpheme that occurs only as part of a larger construction; eg an -s at the end of plural nouns