A second category of tokens is word symbols. Some of the word symbols include the following:

int,  float,  double,  char,  const,  void,  return

Reserved words are also called keywords. The letters that make up a reserved word are
always lowercase. Like the special symbols, each is considered to be a single symbol.
Furthermore, word symbols cannot be redefined within any program; that is, they cannot
be used for anything other than their intended use.