D defs.my
Entry 2 senses Webster, 1913

Stratum

/străt'-əm/ · Stra·tum · IPA /ˈstɹeɪ.təm/
01 n. 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 be…
pl. Stratums, Strata ((#))
  1. 1.
    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.(Geol.)
  2. 2.
    A bed or layer artificially made; a course.