stratum

definition: an abstract place usually conceived as having depth
example:
speech part: noun
synonyms: layer
definition: people having the same social, economic, or educational status
example:
speech part: noun
synonyms: social class socio-economic class class
definition: one of several parallel layers of material arranged one on top of another (such as a layer of tissue or cells in an organism or a layer of sedimentary rock)
example:
speech part: noun
synonyms:

How stratum is being used?