Source : Webster's Revised Unabridged Dictionary (1913)

Pipistrel \Pi*pis"trel\, Pipistrelle \Pip`i*strelle"\, n. [F.
   pipistrelle, It. pipistrello.] (Zo["o]l.)
   A small European bat ({Vesperugo pipistrellus}); -- called
   also {flittermouse}.