Definition of: substratum

(sub·strā′təm, -strat′əm) noun plural ·stra·ta (-strā′tə, -strat′ə)
1. An underlying stratum or layer, as of earth or rock; subsoil.
2. That which forms the foundation or groundwork.
3. Matter or mind considered as the ground of qualities and phenomena; the substance possessing attributes.
4. The substance in which something takes root, as vegetable or animal tissue. [<NL <L, pp. neut. of substernere spread underneath <sub- underneath + sternere strew]
—sub·stra′tive adjective