from
The Collaborative International Dictionary of English v.0.48
Stratum \Stra"tum\, n.; pl. E. {Stratums}, L. {Strata}. The
latter is more common. [L., from sternere, stratum, to
spread; akin to Gr. ? to spread, strew. See {Strew}, and cf.
{Consternation}, {Estrade}, {Prostrate}, {Stratus},
{Street}.]
1. (Geol.) A bed of earth or rock of one kind, formed by
natural causes, and consisting usually of a series of
layers, which form a rock as it lies between beds of other
kinds. Also used figuratively.
[1913 Webster]
2. A bed or layer artificially made; a course.
[1913 Webster]