Form class and Grammatical category

Form class noun - One of the traditional categories of words intended to reflect their functions in a grammatical context.

Grammatical category and form class are semantically related. In some cases you can use "Grammatical category" instead a noun phrase "Form class".

Grammatical category noun - (grammar) a category of words having the same grammatical properties.

Form class and grammatical category are semantically related. Sometimes you can replace phrase "Form class" with "Grammatical category", this phrases are similar.