stratification

definition: the placing of seeds in damp sand or sawdust or peat moss in order to preserve them or promote germination
example:
speech part: noun
synonyms:
definition: the act or process or arranging persons into classes or social strata
example:
speech part: noun
synonyms:
definition: a layered configuration
example:
speech part: noun
synonyms:
definition: forming or depositing in layers
example:
speech part: noun
synonyms:
definition: the condition of being arranged in social strata or classes within a group
example:
speech part: noun
synonyms: social stratification

How stratification is being used?