Source : Webster's Revised Unabridged Dictionary (1913)

Praying \Pray"ing\,
   a. & n. from {Pray}, v.

   {Praying insect}, {locust}, or mantis (Zo["o]l.), a mantis,
      especially {Mantis religiosa}. See {Mantis}.

   {Praying machine}, or {Praying wheel}, a wheel on which
      prayers are pasted by Buddhist priests, who then put the
      wheel in rapid revolution. Each turn in supposed to have
      the efficacy of an oral repetition of all the prayers on
      the wheel. Sometimes it is moved by a stream.