Group' The term 'Class or Category' can be summarized as a GROUP of people, objects, or ideas that share similar characteristics. This term is often used to describe a collection of items that have been organized according to their shared traits. For example, a class or category of animals might include all mammals, while a class or category of books might include all novels. The term 'GROUP' is a synonym for the term 'Class or Category' and can be used interchangeably.