DEFINE

        [SIC\]DEFINE Type Var1 [Keys...] [Var2 [Keys...] [...]] [/GLOBAL]
        [/LIKE VarLike]

    If Type is FUNCTION, define a user-function. If Type is COMMAND,  define
    a  new  user  command.  Otherwise, define new variables of the specified
    type. Type can then be REAL, INTEGER, DOUBLE (for double precision  real
    values), LOGICAL, CHARACTER, or TABLE, HEADER, IMAGE, STRUCTURE or FITS.
    By default, new variables are LOCAL, i.e.  valid only within the current
    macro  and  all  loops or interactive levels called by this macro.  When
    the /GLOBAL switch is specified, the variables are valid at all  levels.
    Local variables are examined before global variables.