ˈstrā]d.əm, ]təm, -ra] also -rä] or -rȧ] noun
( plural strata -d.ə, -tə\ ; also stratums )
Etymology: New Latin, from Latin, spread, bed, from neuter of stratus, past participle of sternere to strew, spread out, lay flat; akin to Greek stratos (encamped) army, Middle Irish srath wide valley — more at strew
1. : a bed or layer artificially made : a coat of some material spread uniformly over a surface or upon another coat : layer
the chaff, packed into a whole bay of the barn, was in strata — Adrian Bell
2.
a. : a tabular mass or thin sheet of sedimentary rock or earth of one kind formed by natural causes and made up usually of a series of layers lying between beds of other kinds
b. : bed
c. : a region of the sea or atmosphere that is analogous to a stratum of the earth
winds tend to drive the surface water away … to be replaced by cold water upwelling from deeper strata — R.E.Coker
d. : a layer of tissue ; especially : one of several superimposed membranes that go to make up an organ
e. : a layer in which archaeological material (as artifacts, skeletons and dwelling remains) is found on excavation
f. : a vertical layer of vegetation (as of herbs, shrubs, or trees) in a plant community
3.
a. : a part of a historical or sociological series representing a period or a stage of development
the technique of skin dressing … belongs to an older stratum of Plains culture than the buffalo-skin tipi — Edward Sapir
b. : a socioeconomic level of society comprised of persons of the same or similar status especially with regard to education or culture — compare class
wide strata of the intellectuals, professionals, and bureaucrats were penetrated ideologically — James Burnham
the upper administrative strata of a typical large factory — E.H.Jacobson & S.E.Seashore
4. : one of a series of layers, levels, or gradations in an ordered system
filtered down to him through different strata of thought — V.L.Parrington
the whole subject of colds is overlaid by stratum upon stratum of folklore, superstition, and pseudoscience — C.H.Andrewes
the more controversial mental strata lying between scientific, philosophical, and theological thought — Times Literary Supplement
the fairy-tale stratum of experience — F.R.Leavis
5. : one of the divisions into which a population is divided in statistical stratification
the counties of the United States may be grouped into 30 or more strata in terms of their population density — L.W.Doob
6. : a group of linguistic phenomena characterized by the possession of common features (as of age or origin)