: a fragment of rock

Examples of clast in a Sentence

Recent Examples on the Web The presolar silicate grains inside the clasts contained significant amounts of the isotope Carbon-13. Elizabeth Rayne, Ars Technica, 2 Aug. 2023 The clasts can then react with water, producing a solution saturated with calcium. Jennifer Ouellette, Ars Technica, 19 Apr. 2023 In other words, these small lime-clast chunks can react with water, post-mixing, to recrystallize as calcium carbonate, and fill cracks while reacting with the ash for further strength. Tim Newcomb, Popular Mechanics, 3 Feb. 2023 Meanwhile, an identical chunk of concrete without the lime-clast structure never healed, and the water just kept flowing through the sample. Daniel Cusick, Scientific American, 18 Jan. 2023 In could reach such an extreme that the biological hitchhikers would cause the pumice to sink or preferential float with one side facing up, creating microenvironments on a single pumice clast! Erik Klemetti, Discover Magazine, 22 Aug. 2012 These differences in bubble shape and density in the same clast is not seen in pumices collected from typical explosive eruptions (like the pumices collected above the ocean surface at Macauley Island). Erik Klemetti, Discover Magazine, 21 Jan. 2013 In geology, a clast is a fragment of an older rock, now broken up and embedded in a younger one. Richard A. Lovett, Outside Online, 16 Nov. 2020 Most of the rock fragments, or clasts, are dark in color, according to Michael Greshko at National Geographic, resembling lunar material. Jay Bennett, Smithsonian, 28 Jan. 2019

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

Word History


Greek klastos broken, from klan to break; perhaps akin to Latin clades disaster

First Known Use

1952, in the meaning defined above

Time Traveler
The first known use of clast was in 1952

Dictionary Entries Near clast

Cite this Entry

“Clast.” Dictionary, Merriam-Webster, Accessed 15 Jul. 2024.

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