Definition of "firefly" []

  • Any of various nocturnal beetles of the family Lampyridae, characteristically having luminescent chemicals in the posterior tip of the abdomen that produce a flashing light. Also called lightning bug. See Regional Note at lightning bug. (noun)
  • Any nocturnal beetle of the family Lampyridae, common in warm and tropical regions, having luminescent abdominal organs (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

  • Any tropical American click beetle of the genus Pyrophorus, esp P. noctiluca, that have luminescent thoracic organs (noun) (c) HarperCollins Publishers Ltd 2016

Use "firefly" in a sentence
  • "But the great thing about it is it does allow somebody to mark a target with what is called a firefly, which is -- it can be a light, a black light, which is not visible on the ground, but which is to somebody flying with night vision goggles."
  • "| Reply my feelings about the series aside, haven’t you all learned that anything new from firefly is just going to turn to crap in your hands? nobody watched the movie, how many people do you think will play the mmo?"
  • "A firefly is a strobe-light which is commonly used for calling in aircraft at night."