stratum
//ˈstreɪtəm//
Noun
stratumSingular
strataPlural
1
A layer or series of layers of rock in the ground.
Geologists discovered a new stratum of rock beneath the surface.
2
A level or class in society to which people are assigned according to their social status, education, or income.
People from different social strata have different opportunities in life.
3
A thin layer within any structure or arrangement.
The scientist examined each stratum of the material under the microscope.