From Middle English schale (“shell, husk; scale”), from Old English sċealu (“shell, husk, pod”), from Proto-West Germanic *skalu, from Proto-Germanic *skalō, from Proto-Indo-European *(s)kelH- (“to split, cut”), from *(s)kel- (“to split, cleave”). See also West Frisian skaal (“dish”), Dutch schaal (“shell”), schalie (“shale”), German Schale (“husk, pod”); also Lithuanian skalà (“splinter”), Old Church Slavonic скала (skala, “rock, stone”), Polish skała (“rock”), Albanian halë (“fish bone, splinter”), Sanskrit कल (kalá, “small part”); also Hittite [script needed] (iškalla, “to tear apart, slit open”), Lithuanian skélti (“to split”), Ancient Greek σκάλλω (skállō, “to hoe, harrow”). Doublet of scale. See also shell.
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A shell, scale or husk; a cod or pod.
the green shales of a beanc. 1610s, Homer (attributed), translated by George Chapman, The Crowne of all Homers Workes: Batrachomyomachia, or the Battaile of Frogs and Mise […], published 1624:
Mr. Lyell next visited the red and green shales of Cabotville, north of Springfield in Massachusetts, where some of the best Ornithichnites have been procured, chiefly in the green shale.1834 October 23, Charles Lyell, “On the fossil foot-prints of birds”, in The American Journal of Science, volume 45, page 395:
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Geography, Geology, Natural sciences A fine-grained sedimentary rock of a thin, laminated, and often friable, structure.
As on all large green roofs, the soil is not dirt exactly but a gravel-like growing medium of granulated pumice, shales, clays and other minerals.2007 March 23, Patricia Leigh Brown, “The Window Box Gets Some Tough Competition”, in The New York Times:
Five years in, ARPA–E’s priorities have shifted, too, for the same reason. The cheap natural gas freed from shale by horizontal drilling and hydraulic fracturing (or fracking) has helped kill off bleeding-edge programs like Electrofuels, a bid to use microbes to turn cheap electricity into liquid fuels, […]2014 March 20, David Biello, “Fracking Hammers Clean Energy Research”, in Scientific American:
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Metonymically The shale oil and shale gas segment of the oil and gas industry.
American shale’s placid responses to energy whirlwinds are becoming an enduring feature of the U.S. oil industry. In recent years, public drillers under investor pressure to be profitable have treated spiking oil prices as an opportunity to return more cash to shareholders—and lock in prices for futures sales. A wave of consolidation has swept out the privately held operators that were quick to add new barrels when prices screened higher. The upshot is that companies aren’t likely to add new rigs unless oil prices hit between $75 and $85 a barrel and stay there for several months, analysts and executives say. […] So far, U.S. shale’s temperance has been a boon to Trump. A steady increase in U.S. production has helped soften spikes in crude prices after his campaigns against Venezuela and now Iran—both major oil producers. The Energy Information Administration expects the national oil output to have hit about 13.7 million barrels a day in February, up nearly 600,000 barrels from when Trump took office. But these gains have been the fruit of technical prowess in the field, not the pursuit of growth. Shale companies have become proficient at drilling fewer but much longer horizontal wells, which allows them to trim costs and still extract more crude. They routinely frack multiple wells at the same time and do so virtually around the clock, which also saves on costs.2026 March 4, Benoît Morenne, “Why American Frackers Aren’t Rushing to Pump More Oil: U.S. shale giants won’t budge from their plans, despite the market chaos”, in The Wall Street Journal:
From Middle English schale (“shell, husk; scale”), from Old English sċealu (“shell, husk, pod”), from Proto-West Germanic *skalu, from Proto-Germanic *skalō, from Proto-Indo-European *(s)kelH- (“to split, cut”), from *(s)kel- (“to split, cleave”). See also West Frisian skaal (“dish”), Dutch schaal (“shell”), schalie (“shale”), German Schale (“husk, pod”); also Lithuanian skalà (“splinter”), Old Church Slavonic скала (skala, “rock, stone”), Polish skała (“rock”), Albanian halë (“fish bone, splinter”), Sanskrit कल (kalá, “small part”); also Hittite [script needed] (iškalla, “to tear apart, slit open”), Lithuanian skélti (“to split”), Ancient Greek σκάλλω (skállō, “to hoe, harrow”). Doublet of scale. See also shell.