flint

from The American Heritage® Dictionary of the English Language, 5th Edition.

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

from The Century Dictionary.

• noun Sheepskin dried in the sun.
• noun An abbreviation of flint-glass.
• noun A form of silica, somewhat allied to chalcedony, but more opaque, and with less luster.
• noun A piece of flinty stone used for any purpose, as for striking fire in a flint-lock musket or otherwise, or in the form of an implement. See cut under flint-lock.
• noun Figuratively, something very hard or obdurate: as, he was flint against persuasion.
• Made or composed of flint.
• Hard and firm, as if made of flint: as, flint corn or flint wheat.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Min.) A massive, somewhat impure variety of quartz, in color usually of a gray to brown or nearly black, breaking with a conchoidal fracture and sharp edge. It is very hard, and strikes fire with steel.
• noun A piece of flint for striking fire; -- formerly much used, esp. in the hammers of gun locks.
• noun Anything extremely hard, unimpressible, and unyielding, like flint.
• noun (Geol.) Same as Stone age, under Stone.
• noun a fire made principially of powdered silex.
• noun See in the Vocabulary.
• noun (Archæol.) tools, etc., employed by men before the use of metals, such as axes, arrows, spears, knives, wedges, etc., which were commonly made of flint, but also of granite, jade, jasper, and other hard stones.
• noun (Pottery), (Mining) An obsolete appliance for lighting the miner at his work, in which flints on a revolving wheel were made to produce a shower of sparks, which gave light, but did not inflame the fire damp.
• noun a hard, siliceous stone; a flint.
• noun a kind of wall, common in England, on the face of which are exposed the black surfaces of broken flints set in the mortar, with quions of masonry.
• noun a solution of silica, or flints, in potash.
• noun [Colloq.] to be capable of, or guilty of, any expedient or any meanness for making money.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A hard, fine-grained quartz that fractures conchoidally and generates sparks when struck.
• noun A piece of flint, such as a gunflint, used to produce a spark.
• noun A small cylinder of some other material of the same function in a cigarette lighter, etc.
• verb transitive To furnish or decorate an object with flint.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a city in southeast central Michigan near Detroit; automobile manufacturing
• adjective showing unfeeling resistance to tender feelings
• noun a hard kind of stone; a form of silica more opaque than chalcedony
• noun a river in western Georgia that flows generally south to join the Chattahoochee River at the Florida border where they form the Apalachicola River