- 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. 2018
- A rock fragment or grain resulting from the breakdown of larger rocks.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.