Stratification (noun)

1. The arrangement or division of a society, group, or population into layers or classes, especially according to social or economic status.
2. The formation or accumulation of layers or deposits, especially in rock formations or soil.

Origin:

Late middle english (in the sense 'arrangement in layers'): from latin stratificatio(n-), from stratificare 'to make into a layer', from stratum 'a layer' + -ficare (from facere 'to make').

Examples:

1. The stratification of society into rich and poor is a persistent issue in many countries.
2. The stratification of the population based on race and gender has been a long-standing challenge for equal opportunity and justice.
3. The stratification of the soil in the region was found to be significant for the growth of crops.
4. The stratification of the rock formations in the area provided important evidence for geological processes.
5. The stratification of the ocean was found to be important for the distribution of marine species and their ecosystems.