A layer of material, especially rock or soil, that lies beneath another layer. The archaeologists carefully removed the topsoil to reveal the substratum of ancient artifacts.
An underlying support or foundation, especially in a conceptual or theoretical context. The substratum of his argument was based on the assumption that all humans seek happiness.
A substance or layer that underlies something, or on which some process occurs, in biology or chemistry. The bacteria were cultured on a nutrient-rich substratum to promote growth.
A language that has lower prestige than a later dominant language and that influences the dominant language through borrowing or structural change. The presence of Celtic loanwords in French points to a Gaulish substratum.