/sys$common/syshlp/helplib.hlb MACRO, VAX MACRO Assembler, Directives, .EXTERNAL (.EXTRN)  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Indicates that the specified  symbols  are  external;  that  is,
    the symbols  are  defined  in another object module and cannot be
    defined until link time

      .EXTERNAL symbol-list

    symbol-list

    A list of legal symbols, separated by commas.

    If the GLOBAL argument is enabled, all unresolved references will
    be marked  as  global  and external.  If GLOBAL is enabled, you
    need not specify .EXTERNAL.   If  GLOBAL  is  disabled,  you  must
    explicitly specify  .EXTERNAL to declare any symbols that are
    defined externally but are referred to in the current module.