The MEAN Stack is a collection of technologies used for building web applications. It consists of four main components: MongoDB, a NoSQL database; Express.js, a web application framework for Node.js; Angular, a front-end framework for building user interfaces; and Node.js, a JavaScript runtime that allows developers to run JavaScript on the server side. Together, these technologies enable developers to create dynamic and responsive web applications. One of the key advantages of the MEAN Stack is that it uses JavaScript throughout the entire development process, from the client side to the server side. This uniformity simplifies the development workflow and allows for easier data exchange between the front end and back end. Additionally, the MEAN Stack is open-source, which means developers can access and modify the code freely, fostering a collaborative environment for innovation.