strata

Strata Marketing Inc. is a Chicago, Illinois-based software company involved in connecting media buyers and sellers. It is owned by Comcast. As of 2010, it processes about $50 billion worth of media buys annually.

In geology and related fields, a stratum (plural: strata) is a layer of sedimentary rock or soil with internally consistent characteristics that distinguish it from other layers. The "stratum" is the fundamental unit in a stratigraphic column and forms the basis of the study of stratigraphy.