of                       Keyword Defining Base Type for Arrays and Sets

 array[...] of <basetype>;
 set of <ordtype>;

    The keyword OF precedes the type specification for any array or set.

      <basetype>    Can be any type whatsoever, including arrays, sets,
                    records, strings, and files.
       <ordtype>    Can only be an ordinal data type, and then only one
                    with 256 or fewer values: Byte, Char, Boolean,
                    enumerated types, or sufficiently small Integer
                    subranges.

  -------------------------------- Example ---------------------------------

           array [5..20] of Boolean;
           array [0..10] of Integer;
           set of Char;