Concrete Method

A concrete method is a method that has code. It is usually the opposite of an abstract method.

A concrete method may be part of an abstract class or not. It may also be overwritten, in a child class, though it is not compulsory, no always the case.

Interfaces cannot have concrete methods.

<?php

abstract class AbstractClass {
    abstract function foo(); // abstract method

    function goo() {
        return 1;
    } // concrete method
}

class ConcreteClass extends AbstractClass{

    function foo() {
        return 2;
    } // concrete method

    // No need to redefine the concrete methods.
    // Yet, it is still possible
}

?>

Documentation

See also PHP: Abstract Classes, Interfaces, and Traits Explained.

Related : Final Keyword, Concrete Class, Abstract Method, Abstract Class