Definition of "regolith" [regolith]

• The layer of loose rock resting on bedrock, constituting the surface of most land. Also called mantle rock. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Deimos appears mostly smooth due to a covering of powdery rock called regolith, which is reddish in this color-enhanced picture."
• "Schultz said the silver molecules detected were in atomic form - loosely attached to grains of lunar soil, or "regolith" - and were not the kind of deposits that could be mined."
• "Over this weekend, NASA just held a competition in California with $750,000 in prizes for anyone in America who could move the most "regolith" --- or moon dirt --- with a robot."