A "Full-Stack" developer is a professional who is skilled in both the front-end and back-end aspects of web development. The front-end refers to the part of a website that users interact with, including design and user experience, while the back-end involves server-side programming, databases, and application logic. Full-Stack developers can work on all layers of a web application, making them versatile and valuable in the tech industry. Being a Full-Stack developer often requires knowledge of various programming languages and frameworks. Common front-end technologies include HTML, CSS, and JavaScript, while back-end technologies may involve Node.js, Python, or Ruby on Rails. This broad skill set allows Full-Stack developers to build complete web applications from start to finish.