sco·​ria ˈskȯr-ē-ə How to pronounce scoria (audio)
plural scoriae ˈskȯr-ē-ˌē How to pronounce scoria (audio)
: the refuse from melting of metals or reduction of ores : slag
: rough vesicular cindery lava
scoriaceous adjective

Example Sentences

Recent Examples on the Web AlaskaVeniaminof continues to be active in the Aleutian arc and the latest NASA Earth Observatory imagery (above) captures the small ash plume (and ash deposits) along with the small lava flow that continues to issue from the scoria cone within the main caldera. Erik Klemetti, Discover Magazine, 16 Aug. 2013 There is archaeological evidence that people moved 30 kilometers to the north because much of the area near Sunset Crater was covered in coarse volcanic scoria. Erik Klemetti, Discover Magazine, 7 Mar. 2017 The new eruption at the volcano is likely sourced from one of the two small scoria cones within the caldera. Erik Klemetti, Discover Magazine, 13 June 2013 Larger eruptions of El Reventador, including a VEI 4 eruption in 2002 (see above), have been known to coat Quito with ash (90 km away) and within the 2002 crater, a small scoria cone and lava dome have grown since 2008. Erik Klemetti, Discover Magazine, 25 Jan. 2013 The Campei Flegrei is a large caldera system that most recently produced Monte Nuovo, a scoria cone on the north shore of the Bay of Naples. Erik Klemetti, Discover Magazine, 31 July 2012 Emi Koussi, beyond being MVP #19, is a large shield volcano with a prominent summit caldera along with a number of small parasitic scoria cones on its flanks. Erik Klemetti, Discover Magazine, 21 Feb. 2011 As if the Easter Island statues weren’t enigmatic enough, a few of them are wearing hats—6.5-foot-wide, 13-ton cylinders of cindery red volcanic rock called scoria. Kiona N. Smith, Ars Technica, 5 June 2018 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'scoria.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


Middle English, from Latin, from Greek skōria, from skōr excrement — more at scatology

First Known Use

14th century, in the meaning defined at sense 1

Time Traveler
The first known use of scoria was in the 14th century

Dictionary Entries Near scoria

Cite this Entry

“Scoria.” Dictionary, Merriam-Webster, Accessed 9 Jun. 2023.

Kids Definition


sco·​ria ˈskōr-ē-ə How to pronounce scoria (audio)
plural scoriae -ē-ˌē How to pronounce scoria (audio)
: rough cindery lava

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