a grain of sediment, silt, sand, gravel, etc., especially as a constituent fragment of a clastic rock formation, as distinguished from a chemical or biogenic component of such a formation.
Origin of clast
First recorded in 1950–55; probably back formation from clastic
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
A rock fragment or grain resulting from the breakdown of larger rocks.
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