Source : Webster's Revised Unabridged Dictionary (1913)

Hoop \Hoop\, v. i. [OE. houpen; cf. F. houper to hoop, to shout;
   -- a hunting term, prob. fr. houp, an interj. used in
   calling. Cf. {Whoop}.]
   1. To utter a loud cry, or a sound imitative of the word, by
      way of call or pursuit; to shout. [Usually written
      {whoop}.]

   2. To whoop, as in whooping cough. See {Whoop}.

   {Hooping cough}. (Med.) See {Whooping cough}.