noun pl. strata or stratums
- a horizontal layer or section of material, esp. any of several lying one upon another; specif.,
- Biol. a layer of tissue
- Geol. a single layer of sedimentary rock
- a section, level, or division, as of the atmosphere or ocean, regarded as like a stratum
- any of the socioeconomic groups of a society as determined by birth, income, education, etc.
ModL < L, a covering, blanket < stratus, pp. of sternere, to spread, stretch out, cover: for IE base see strew