A class of linguistic forms with grammatical or syntactic features in common; a part of speech or subset of a part of speech.
〔语言学〕类，形（式）类；词类，词类子集
Example sentencesExamples
You'll also find that linguistic grammar talks about form and function, structure and form classes.
The notional definition of a noun does not cover such words as action, existence, happiness, temperature that belong to the noun form class on formal criteria.
Definition of form class in US English:
form class
noun
Linguistics
A class of linguistic forms with grammatical or syntactic features in common; a part of speech or subset of a part of speech.
〔语言学〕类，形（式）类；词类，词类子集
Example sentencesExamples
The notional definition of a noun does not cover such words as action, existence, happiness, temperature that belong to the noun form class on formal criteria.
You'll also find that linguistic grammar talks about form and function, structure and form classes.