BSD (Berkeley Software Distribution) is a family of UNIX-like operating systems originally developed at the University of California, Berkeley. BSD introduced many features and improvements to UNIX, influencing the development of modern operating systems. Today, several BSD variants, such as FreeBSD, OpenBSD, and NetBSD, are known for their stability, security, and open-source licensing. BSD code has also contributed to other systems, including MacOS. Its permissive licensing allows developers to use, modify, and distribute the software freely, making BSD a significant foundation in the history of computing.