noun, plural fire·flies.
- any nocturnal beetle of the family Lampyridae, characterized by a soft body with a light-producing organ at the rear of the abdomen.
noun plural -flies
- any nocturnal beetle of the family Lampyridae, common in warm and tropical regions, having luminescent abdominal organsSee also glow-worm
- any tropical American click beetle of the genus Pyrophorus, esp P. noctiluca, that have luminescent thoracic organs