substratum
/ˈsʌbˌstreɪtəm/
noun
- A layer or material that lies underneath something, especially in the ground or in a structure.
- Plants with deep roots can reach the moist substratum under the dry topsoil.
- The road's substratum of gravel helps prevent cracks in the pavement.
- The builders found a hard rock substratum just below the soil.
- A foundation or underlying basis for something, such as an idea, system, or culture.
- Economic stability is the substratum on which the country's growth depends.
- The ancient language formed a substratum for many modern dialects.
- Trust is the substratum of any healthy relationship.
Synonyms