Definitions

1. noun

The lowest layer or stratum of a system, especially the underlying soil or geological formation that supports a particular ecosystem or structure.

“The coral reef’s substratum provides a habitat for a diverse array of marine life.”

2. noun

A fundamental or underlying principle or structure, especially in philosophy or theology.

“Plato’s metaphysical theories posited the substratum of the universe as a realm of eternal, abstract Forms.”

3. noun

A lower or underlying layer of something, especially a layer of a solution or a mixture.

“The substratum of the mixture was a dense, syrupy liquid.”