The Collaborative International Dictionary of English v.0.48:
Owlet \Owl"et\, n. [Dim. of owl. Cf. Howlet.] (Zool.) A small owl; especially, the European species (Athene noctua), and the California flammulated owlet (Megascops flammeolus). [1913 Webster] Owlet moth (Zool.), any noctuid moth. [1913 Webster]WordNet (r) 3.0 (2006):
Athene noctua n 1: small European owl [syn: little owl, Athene noctua]