Anonymous Function

A function may be instantiated, without defining a function name. Such functions are called anonymous.

In PHP, they are defined as closures or arrow functions. They may also be created based on existing methods and functions, with the … operator.

Even without names, they are usable just like functions, or as callable.

<?php
     $closure = function () {} ;

     $arrowFunction = fn() => 1;

     $fcs = strlen(...);
?>

Documentation

See also Anonymous functions in PHP

Related : Closure, Arrow Functions, First Class Callable, Closure, Anonymous, Arrow Functions