Operand

An operand is an argument for an operator. It applies to any of the operand: to differentiate them later, they are named with their position (first, second, etc.), or their name.

<?php

// One operand
$b = !$a;

// two operands
$a = 1 + 3;

// Three operands
$c = $a ? 2 : 4;

?>

Related : Addition, Unary Operator, Ternary Operator, Bitshift Operators