The Collaborative International Dictionary of English v.0.48:

Pipistrel \Pi*pis"trel\, Pipistrelle \Pip`i*strelle"\, n. [F.
   pipistrelle, It. pipistrello.] (Zool.)
   A small European bat (Vesperugo pipistrellus); -- called
   also flittermouse.
   [1913 Webster]