(1) In object-oriented languages such as Objective-C and Java, a prototype for a particular kind of object. A class definition declares instance variables and defines methods for all members of the class. Objects that belong to the same class have the same types of instance variables and have access to the same methods (included the instance variables and methods inherited from superclasses). (2) In AppleScript, a category for objects that share characteristics such as properties and elements and respond to the same commands.