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.]
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.
A bed or layer artificially made; a course.
© Webster 1913.