WordPress sites' most common software infrastructure is called the LAMP stack: Linux, Apache, MySQL, and PHP.
Linux is the operating system on which most web servers (the computers that store websites) run. However, servers can run on other operating systems, such as Windows or Mac OS, making "WAMP" and "MAMP" common configurations for people who create servers on their own computers to do local development.
Apache is the most common HTTP web server software. Server software allows servers to process and respond to requests for information ("HTTP requests") sent by remote computers, making the interactivity of the internet possible. Nginx is an increasingly popular alternative to Apache.
MySQL refers to the structure of WordPress databases. Every WordPress site has a database, which stores and communicates crucial things like post and page contents, site settings, and users and us...