PHP

PHP is a programming language made for the web. Rasmus Lerdorf created it in 1994 as a few tools for his personal home page, which is where the name first came from; today it officially stands for "PHP: Hypertext Preprocessor". It runs on the server, not in your browser.

Here is what it does. When you open a page on a PHP site, the web server runs the PHP code for that page: it might check whether you are logged in, fetch the latest posts from a database and then put together the HTML. Your browser only receives the finished page and never sees the PHP.

Programmers love to make fun of PHP, but it quietly powers a huge part of the web. WordPress, the system behind a large share of the world's websites, is written in PHP, and so is the software that runs Wikipedia. Modern PHP, with frameworks like Laravel and Symfony, is a very different language from the messy scripts of the early 2000s.