stratum
noun(stra-tum)
a bed or layer artificially made
stratum
noun(stra-tum)
a sheetlike mass of sedimentary rock or earth of one kind lying between beds of other kinds
stratum
noun(stra-tum)
a region of the sea or atmosphere that is analogous to a stratum of the earth
stratum
noun(stra-tum)
the outer part of the epidermis consisting chiefly of layers of dead flattened nonnucleated cells filled with keratin