LEMP is an acronym for a group of open-source software that is frequently employed to deliver web apps. The abbreviation LEMP stands for the architecture of a Linux operating system with a nginx (pronounced engine-x, hence the E in the acronym) web server, site information held in a MySQL database, and dynamic content handled by PHP.
The LEMP stack is one approach to configure a web server and is utilized in a variety of large-scale web app projects.