bedrock
n. uncountable C1 Advanced US //ˈbɛˌdɹɑk// UK //bˈɛdɹɒk// bedrock
n. the solid rock that lies under the loose soil on the ground. It also means the basic ideas or facts that support a whole system.
n. the solid rock underlying surface materials such as soil or gravel; figuratively, the fundamental principles on which something is based.
Honesty is the bedrock of a good relationship.
The engineers had to drill deep into the earth to anchor the skyscraper's foundation into the bedrock.
The principle of free speech is considered the bedrock of democratic society, providing the essential framework for all other civil liberties to function effectively.
From bed (“a layer on top of which something else rests.”) + rock.
Usage
Often used figuratively with the preposition 'of' to describe a foundation for abstract concepts.