# Classes and class members

Returning to our real-world cat for a moment, there are many cats of different colors, ages, with different names, and with different ways of eating and purring. But we can still assert that all cats belong to a certain class of object, an object of type "cat". Each actual (real-world) cat is an instance of the cat class type.

Likewise, in object-oriented programming, a class defines a blueprint for a type of object. The properties and behaviors belong to a class are referred to as members of that class. The properties of the class (in our cat example, name, age, and color) are represented as variables belonging to the class; behaviors (eating, sleeping) are represented as functions of the class, or methods.

For example, we could create a Person class, and then create individual person would be an instance of that class containing all the properties and methods of the class.

In ActionScript, you define a class with the `class` statement. For more information see "About ActionScript 2 class files" on page 133.ActionScript includes a number of built-in classes, such as the MovieClip, TextField, and String classes. For more information on using these classes, see Using Built-In Objects in ActionScript.