one of the grammatical groups, such as noun, verb, and adjective, into which words are divided depending on their use

The checklist contained 403 items of various word classes, including 136 verbs and 201 nouns. 这张清单中有403个不同词类的词条，包括了136个动词和201个名词。

Of course, the same word form may occur in more than one word class. 当然，同一个词（型）可能出现在不止一种词类中。