The Mean Stack is a popular web development framework that combines four key technologies: MongoDB, Express.js, Angular, and Node.js. Each component plays a specific role: MongoDB is a NoSQL database that stores data in a flexible format, Express.js is a web application framework for building server-side applications, Angular is a front-end framework for creating dynamic user interfaces, and Node.js allows JavaScript to be used on the server side. This stack enables developers to use a single programming language, JavaScript, throughout the entire development process, from the client side to the server side. This uniformity simplifies the development workflow and enhances productivity, making the Mean Stack a favored choice for building modern web applications.