PHP is an acronym for "PHP: Hypertext Preprocessor"
PHP is a server scripting language, and a powerful tool for making dynamic and interactive Web pages.
PHP is a widely-used, free, and efficient alternative to competitors such as Microsoft's ASP.
PHP scripts are executed on the server.
PHP is a widely-used, open source scripting language
PHP code are executed on the server, and the result is returned to the browser as plain HTML
eg a simple helloworld.php code:
<?php echo "hello world"; ?>