overriding

Providing a different implementation of a method in a subclass of the class that originally defined the method.

Hiding or invalidating some other definition of the same name. (Not to be confused with "overloading", which adds definitions that must be disambiguated some other way.) To confuse the issue further, we use the word with two overloaded definitions: to describe how you can define your own "subroutine" to hide a built-in "function" of the same name (see "Overriding Built-in Functions" in perlsub) and to describe how you can define a replacement "method" in a "derived class" to hide a "base class"'s method of the same name (see perlobj).