A Servlet is a Java programming component that runs on a web server and handles client requests. It processes incoming data, generates dynamic web content, and sends responses back to the client, typically in the form of HTML. Servlets are part of the Java EE (Enterprise Edition) platform and are used to create web applications. Servlets operate within a Java Servlet Container, which manages their lifecycle, including loading, instantiation, and destruction. They can interact with other Java technologies, such as JSP (JavaServer Pages) and JavaBeans, to create robust and scalable web applications.