stratum
    n 1: 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)
    2: people having the same social, economic, or educational
       status; "the working class"; "an emerging professional class"
       [syn: class, stratum, social class, socio-economic
       class]
    3: an abstract place usually conceived as having depth; "a good
       actor communicates on several levels"; "a simile has at least
       two layers of meaning"; "the mind functions on many strata
       simultaneously" [syn: level, layer, stratum]

Stratum \Stra"tum\, n.; pl. E. Stratums, L. Strata. The
   latter is more common. [L., from sternere, stratum, to
   spread; akin to Gr. ? to spread, strew. See Strew, and cf.
   Consternation, Estrade, Prostrate, Stratus,
   Street.]
   1. (Geol.) 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.
      [1913 Webster]

   2. A bed or layer artificially made; a course.
      [1913 Webster]