Which construct is not part of exception handling in PHP?

The construct that is not part of exception handling in PHP is "define." In PHP, exception handling is primarily managed using the constructs try, catch, and throw.

The try block is used to wrap code that might throw an exception. If an exception occurs within this block, PHP checks for a corresponding catch block that can handle the exception. The catch block allows you to take specific actions based on the type of exception that was thrown. The throw statement is used to trigger an exception, allowing you to create custom error conditions within your code.

In contrast, define is a construct used for defining constants in PHP, which serves a different purpose unrelated to error handling or exceptions. Since it does not play any role in managing or responding to exceptions, it is correctly identified as the answer to this question.