/eg-zek'/ vt.,n. 1. [UNIX from `execute'] Synonym for chain, derives from the `exec(2)' call. 2. [from `executive'] obs. The command interpreter for an OS (see shell); term esp. used around mainframes, and prob. derived from UNIVAC's archaic EXEC 2 and EXEC 8 operating systems. 3. At IBM and VM/CMS shops, the equivalent of a shell command file (among VM/CMS users). The mainstream `exec' as an abbreviation for (human) executive is *not* used. To a hacker, an `exec' is a always a program, never a person.