Form class and Syntactic category

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

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

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

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