An operator is a special type of method that at run-time introduces or modifies how a primitive operates. For example:

operator * (Left:String; Right:Int32): String;
begin
  Result := '';
  for 1 to Right do
    Result := Result + Left;
end;

The code above modifies Modern Pascal that String now has the ability to multiply. Making the following code valid:

var
   str:String;

Begin
   str:='abc' * 3;
   Writeln(str);
end.

Output:
    abcabcabc