In geology, bedrock is solid rock that lies under loose material (regolith) within the crust of Earth or another terrestrial planet.
https://github.com/davepinch/pinchy.cc/blob/master/content/topics/geology/rocks/bedrock/wikipedia/en.wikipedia.org.md
The various kinds of broken and weathered rock material, such as soil and subsoil, that may overlie the bedrock are known as regolith.