PHP define() Function

The define() function defines a constant.

bool define ( string $name , mixed $value [, bool $case_insensitive = FALSE ] )

Defines a named constant at runtime.

Example -

Parameter	Description
name	The name of the constant.

Return Values

The value of the constant. In PHP 5, value must be a scalar value (integer, float, string, boolean, or NULL). In PHP 7, array values are also accepted.