A bedrock is the solid foundation or base of something.
When people talk about the bedrock of a relationship, they mean the strong and steady part that keeps it going. This can be a feeling of trust between partners, or a deep connection that helps them work through tough times together. If you think about it, just like how rocks form the solid foundation under our feet, a bedrock in a relationship is the unshakeable part that keeps everything stable.
The word "bedrock" can also refer to actual rock or stone. In geology, for example, scientists might talk about the bedrock of an area being made up of granite or sandstone. This is just another way of saying what kind of rocks are found at the bottom or base of a particular place.
The solid rock that exists at some depth below the ground surface. Bedrock is rock "in place", as opposed to material that has been transported from another location by weathering and erosion.
