The Free On-line Dictionary of Computing (19 January 2023):

PHP: Hypertext Preprocessor
PHP

    (PHP) An Open Source,
   server-side, cross-platform, scripting language used to
   create dynamic web pages.

   PHP can be embedded in HTML using special tags like:

    Hello World
'; ?>

   This is stored in a file with a ".php" extension.  The web
   server passes the file to the PHP interpreter which
   executes the code in the  tags.  The tagged code
   is then replaced with its output, typically ordinary HTML, in
   the response sent to the web browser.

   PHP is a recursive acronym.

   PHP Home (http://php.net/).

   Cheat sheet
   (http://addedbytes.com/cheat-sheets/php-cheat-sheet/).

   (2010-03-20)