stratum
[ strey-tuhm, strat-uhm ]
a layer of material, naturally or artificially formed, often one of a number of parallel layers one upon another
USE 1
The archaeologist carefully excavated each stratum to uncover artifacts from different historical periods.
USE 2
In urban planning, the socioeconomic stratum of a neighborhood can influence the types of services and infrastructure provided.
USE 3
As we hiked through the canyon, we could see the distinct stratum of rock formations, each telling a different geological story.