1. A light with a reflector and lens mounted on the front of a locomotive, automobile, or other vehicle. Also called headlamp.
2. A lamp mounted on a miner's or spelunker's hard hat.

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.