noun (n)

• 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)(noun.location)

  source: wordnet30
• people having the same social, economic, or educational status(noun.group)

  Synonym:
  class, social class, socio-economic class
  

  source: wordnet30
• an abstract place usually conceived as having depth(noun.cognition)

  Synonym:
  layer, level
  

  source: wordnet30
• A bed of earth or rock of one kind, formed by natural causes, and consisting usually of a series of layers, which form a rock as it lies between beds of other kinds. Also used figuratively.(noun)

  source: webster1913