Substratum (noun)

The underlying layer, material, or substance that serves as a foundation or base.

Origin:

Derived from the latin word "substratum", meaning "something that lies underneath".

Examples:

1. The substratum of the ocean floor is made up of sediment and rock.
2. The substratum of the forest is composed of fallen leaves and twigs.
3. The substratum of the city is built on top of a layer of rock and clay.
4. The substratum of a language is made up of its basic grammar and vocabulary.
5. The substratum of a culture is composed of its shared beliefs, values, and traditions.