light bulb

Noun

light bulb (plural light bulbs)

1. An evacuated glass bulb containing a metal filament which is heated by electrical resistance to produce light.
   • Atticus did something that interested us: he came into the livingroom carrying a long electrical extension cord. There was a light bulb on the end.1960 July 11, Harper Lee, chapter 15, in To Kill a Mockingbird, Philadelphia, Pa.; New York, N.Y.: J[oshua] B[allinger] Lippincott Company, →OCLC

   Synonyms:

   bulb, glow-lamp, incandescent lamp, light globe

2. (broadly) An article that resembles such a bulb and converts electricity to light by any process.
   • a fluorescent light bulb
   • an LED light bulb
3. (figuratively) Used in reference to the sudden arrival of a realization, an inspiration, an idea, or the like.
   • a light-bulb moment
   • Figuratively speaking, a light-bulb flashed over Galvin's head early this year, and in March–along […]1949, Forbes, volume 64, page 18