Source : Webster's Revised Unabridged Dictionary (1913)

AEolipile \[AE]*ol"i*pile\, AEolipyle \[AE]*ol"i*pyle\, n. [L.
   aeolipilae; Aeolus god of the winds + pila a ball, or Gr. ?
   gate (i. e., doorway of [AE]olus); cf. F. ['e]olipyle.]
   An apparatus consisting chiefly of a closed vessel (as a
   globe or cylinder) with one or more projecting bent tubes,
   through which steam is made to pass from the vessel, causing
   it to revolve. [Written also {eolipile}.]

   Note: Such an apparatus was first described by Hero of
         Alexandria about 200 years b. c. It has often been
         called the first steam engine.