The Collaborative International Dictionary
AEolipyle
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.
Wiktionary
aeolipyle
n. (alternative form of aeolipile English)