Meaning of halogen lamp

hal'ogen lamp"

Pronunciation: [key]
  1. a gas-filled, high-intensity incandescent lamp having a tungsten filament and containing a small amount of a halogen, such as iodine, that vaporizes on heating and redeposits any evaporated tungsten particles back onto the filament: used esp. in motion-picture projectors and automobile headlights.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.