Short for Virtual Address eXtension, Digital Equipment Corporation's successor to its PDP-11 line of minicomputers. As its name implies, VAX systems feature an operating system—VMS—that supprts virtual memory. The VAX was introduced in 1977 and reached its pinnacle of success in the mid-1980s. It has been sclipsed by RISC-based workstations, including DEC's own line of Alpha stations. (© Webopedia)