noun, plural sub·stra·ta [suhb-strey-tuh, -strat-uh, -suhb-strey-tuh, -strat-uh] /ˈsʌbˌstreɪ tə, -ˌstræt ə, -sʌbˈstreɪ tə, -ˈstræt ə/, sub·stra·tums.
Examples from the Web for substratum
The substratum of the community remains, however, such as I have shown it.South America To-day|Georges Clemenceau
It goes by the name of jaung, and is a light soil, with a substratum of sand from six to twelve inches below the surface.The Commercial Products of the Vegetable Kingdom|P. L. Simmonds
Instead of blowing plates of solid red, the old glass-makers used to flash a thin layer of red over a substratum of plain glass.
Opposite as the two men were in every trait, a substratum of affinity came out in this deadlock of their glances.The Incendiary|W. A. (William Augustine) Leahy
Unfortunately, however, we shall find that this case is actually made the substratum of the law.The History Of The Last Trial By Jury For Atheism In England|George Jacob Holyoake
British Dictionary definitions for substratum
noun plural -strata (-ˈstrɑːtə, -ˈstreɪtə)
- the solid rock underlying soils, gravels, etc; bedrock
- the surface to which a fixed organism is attached