|səb+ noun
( plural substrata also substratums )
Etymology: Medieval Latin, from neuter of Latin substratus, past participle of substernere to spread under, strew under, from sub- + sternere to strew — more at strew
: something that is laid or spread under or that underlies and supports or forms a base for something else : an underlying structure, layer, or part : foundation: as
a.
(1) : a permanent characterless support of properties of a thing or reality : substance as a support of attributes
(2) : such a support regarded as a cause of a thing or its properties
b. : the material of which something is made and from which it derives its special qualities
protoplasm is the material substratum of life
c. : a layer of rock or earth beneath the surface soil ; specifically : subsoil
d. : substrate 2, 3
e. : a thin coating (as of hardened gelatin) on the support of a photographic film or plate to facilitate the adhesion of the sensitive emulsion
f. : a language that is extinct in a particular region but is believed by some linguists to have left traces of its structure in a current or more recently introduced language of that region as a result of imperfect learning of the introduced language by the native population