understratum

(redirected from understratums)
Also found in: Medical.

un·der·stra·tum

 (ŭn′dər-strā′təm, -străt′əm)
n. pl. un·der·stra·ta (-strā′tə, -străt′ə) or un·der·stra·tums
A substratum.

understratum

(ˈʌndəˌstrɑːtəm)
n, pl -ta (-tə) or -tums
(Physical Geography) the layer of soil underneath the soil on the surface; a substratum or subsoil