A set of CLasses and their interrelationships. One CLass may be a specialisation (a "subCLass" or "{derived CLass}") of another which is one of its "{superCLasses}" or "base CLasses". When a method is invoked on an object it is first looked for in the object' s CLass, then the superCLass of that CLass, and so on up the hierarchy until it is found. Thus a CLass need only define those methods which are specific to it, and inherits methods from all its superCLasses. See also: multiple inheritance. (1997-08-06)