Library /sys$common/syshlp/sca$menu.hlb Terms, Compunit  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  The smallest piece of source code that can be
  separately compiled. (For example, in FORTRAN, a
  subroutine or function; in C, a single file.) Some
  languages allow you compile one or more compilation
  units at a time. SCA considers the units to be
  separate.)