1. a layer of rock, earth, or other material
Usage: geology
2. a level or class in society
3. one of a series of layers or levels

Examples

• The archaeologists discovered pottery in the lowest stratum of the dig site.
• Each rock stratum tells a story about Earth's geological history.
• The upper stratum of society lived in luxury while others struggled.
• Social mobility allows people to move between different strata.
• The atmosphere consists of several distinct strata with different properties.
• Researchers studied each stratum of the ancient settlement carefully.