1. A very hard, fine-grained quartz that sparks when struck with steel.
2. 1. A piece of flint used to produce a spark.
   2. A small solid cylinder of a spark-producing alloy, used in lighters to ignite the fuel.
3. A piece of flint used as a tool by prehistoric humans.
4. Something resembling flint in hardness: a jaw of flint.

[Middle English, from Old English.]

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.