Stratification

Stratification is the building up of layers of deposits, and can have several variations of meaning:

Social stratification, is the dividing of a society into levels based on wealth or power.
Stratification in archaeology are the layers in which objects are found.
Stratification (botany).
See stratified sampling for the use of stratification in survey sampling. The term "stratified sampling" is also refers a method of variance reduction in Monte Carlo methods.
In logic, stratification is a layering of predicate symbols to guarantee unique interpretations and to avoid paradoxical definitions like Russell's paradox.
Stratification is a separate meaning as applied to manifolds, and singularity theory, of a decomposition into pieces with specified relationships on fitting together.
In music stratification is a layering of musical texture or the independent operating of more than one parameter simultaneously (see auditory stream).