Definition of "shale" []

• A fissile rock composed of layers of claylike, fine-grained sediments. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Heating oil shale to a sufficiently high temperature will drive off a vapor which processing can distill (retort) to yield a petroleum-like shale oil-a form of non-conventional oil-and combustible shale gas (the term shale gas can also refer to gas occurring naturally in shales)."
• "The amount of water it takes to get that oil shale is pretty much all the water we have."
• "Bloomberg News Drilling in shale-gas formations, as here near Montrose, Pa., has contributed to a near-record U.S. supplies of natural gas."