WordNet (r) 3.0 (2006):

EXEC
    n 1: the chief executive department of the United States
         government [syn: White House, EXEC]

The Jargon File (version 4.4.7, 29 Dec 2003):

exec
 /eg?zek'/, /eks?ek/, 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 always a program, never a person.


The Free On-line Dictionary of Computing (30 December 2018):

EXEC

    An early batch language for the IBM VM/CMS
   systems.

   [SC19-6209 Virtual Machine/ System Product CMS Command and
   Macro Reference, Appendix F. CMS EXEC Control Statements].

   [Was EXEC 2 was a later version?]

   (2000-08-06)


The Free On-line Dictionary of Computing (30 December 2018):

exec

   /eg-zek'/  1. execute.

   A synonym for chain derived from the Unix "exec" system
   call.

   Unix manual page: execve(2).

   2. (Obsolete) executive.

   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.

   3. At IBM and VM/CMS shops, the equivalent of a shell
   command file.

   4.  The innermost kernel of the Amiga
   operating system which provides shared-library support,
   device interface, memory management, CPU management, basic
   IPC, and the basic structures for OS extension.  The rest of
   the Amiga OS (windowing, file system, third-party extensions,
   etc.) is built using these structures.

   [Jargon File]

   (1997-08-01)