1. The strings are a category of musical instruments.
    弦乐器是乐器的一种。

2. There are different categories of books in a library.
    图书馆里有各种不同种类的书籍。

3. Time, place, quantity and quality are categories.
    时、空、质、量都是范畴。

1. 种类;类别
    If people or things are divided into categories, they are divided into groups in such a way that the members of each group are similar to each other in some way.

    e.g. This book clearly falls into the category of fictionalised autobiography...
           这本书很显然属于自传体小说。
    e.g. The tables were organised into six different categories...
           餐桌被编为6个不同的类别。

1. a general concept that marks divisions or coordinations in a conceptual scheme

2. a collection of things sharing a common attribute

    e.g. there are two classes of detergents

    Synonym: classfamily