Operators

An operator is something that takes one or more values (or expressions, in programming jargon) and yields another value (so that the construction itself becomes an expression).

<?php

// not operator, unary
$a = !$b;

// plus operator
$c = $d + 2;

// ternary operator
$e = $d ? 3 : 2;

?>

Documentation

Related : Short Tags, Short Syntax