Overwrite

Overwriting is the process to replace a method, property or constant that was defined in a parent, by a local definition. This is related to OOP programming and inheritance.

Overwriting is applicable to constants, methods and properties. Methods still should have a compatible signature with their parent’s equivalent, while properties and constants may change their (default) value.

Overwriting is prevented by the final keyword, or the private visibility.

Overwriting is also called overloading.

<?php

class x {
    const Y = 1;
    const Z = 2;
}

class xx extends x {
    // Z is inherited, and its value is 2
    // Y used to be 1, it is now 31
    const Y = 31;
    const A = 3;
}

?>

Documentation

Related : Final Keyword, Private Visibility, Inheritance