From Longman Dictionary of Contemporary Englishfireflyfire‧fly /ˈfaɪəflaɪ $ ˈfaɪr-/ noun (plural fireflies) [countable] HBIan insect with a tail that shines in the dark
Examples from the Corpus
firefly• Anne's husband, Cuthbert, said there'd be fireflies tonight.• Her firefly eyes clicked open and closed, and along her forehead the horizontal grooves had deepened into sharp narrow ruts.• So many green sparkles, so many fireflies.• The dark wood was now lit up with lurid flashes of artillery and the firefly sparkle of rifles....• The crickets had started up; next the fireflies would alight, but not as many as when Petey was small.• The firefly of a psychic spirit gleaming in the nightscape of existence: ah, that he could pinpoint by and large.• Since glow-worms, fireflies, electric eels and many fish exhibit a similar phenomenon, the statement is not unrealistic. 