SSL stands for Secure Sockets Layer. It is a standard technology that ensures the secure and encrypted communication between a user's web browser and a website's server. SSL is commonly used to secure data transfer, such as login credentials, credit card information, and other sensitive information exchanged on the internet.

SSL works by establishing a secure connection between the user's browser and the server, encrypting the data transmitted between them. This encryption helps protect the information from being intercepted or tampered with by malicious entities. When a website has an SSL certificate installed, the URL typically starts with "https://" instead of "http://," indicating a secure connection.

SSL has been succeeded by Transport Layer Security (TLS), which is an updated and more secure protocol. However, the term "SSL" is often used colloquially to refer to both SSL and TLS technologies.