noun, plural: strata
(1) (histology) Any from the layers of tissues arranged one atop another, thus forming an anatomical structure
(2) (ecology) A layer of plants or vegetation usually of the same or similar height
(3) (general) One of the stack of horizontal layers
(Histology) The skin is an example of biological material comprised of several strata (or layers of tissues).
(Ecology) In a plant community, a stratum implicates dominance of that plant species.
Word origin: Latin strātum from strātus or sternere (to spread, strew)