what does stratum
â¢ STRATUM (noun). The noun STRATUM has 2 senses: 1. one of several parallel layers of material arranged one on top of another (such as a layer of tissue or cells in an organism or a layer of sedimentary rock).2. an abstract place usually conceived as having depth. Familiarity information: STRATUM used as a noun is rare.. one of several parallel layers of material arranged one on top of another (such as a layer of tissue or cells in an organism or a layer of sedimentary rock). 2. an abstract place usually conceived as having depth. Familiarity information: STRATUM used as a noun is rare.