firefly

Reading level: hard

Estimated CEFR level: C2 — Proficiency

Estimated from word frequency; not an official CEFR classification.

Definition

noun tropical American click beetle having bright luminous spots
noun nocturnal beetle common in warm regions having luminescent abdominal organs

Endocentric compound of fire + fly, because the insects glow; whence also lightning bug. Compare glow fly, glowworm, and lanternfly.

They danced like giant fireflies. — The Long Roll, Mary Johnston
"The proprietor of 'The Firefly.'" — The Silent Barrier, Louis Tracy
"Perhaps it's a big firefly," said another. — McGuffey's Third Eclectic Reader, William Holmes McGuffey

fire beetle, Pyrophorus noctiluca

Type a word, a sentence, a book title, or a link to an English article. WordNet and the Classics answer.

Try

A library of classics · a vault of words · instant etymology & meaning