word class vs form class

word class and form class both are nouns.

Word	Noun	Adjective	Verb	Adverb
word class	Yes	No	No	No
form class	Yes	No	No	No

As nouns, word class and form class are synonyms defined as:

word class and form class: one of the traditional categories of words intended to reflect their functions in a grammatical context

Other synonyms of word class include part of speech.

word class (noun)	form class (noun)
one of the traditional categories of words intended to reflect their functions in a grammatical context	one of the traditional categories of words intended to reflect their functions in a grammatical context