stratum

When wage gains cluster in the top income strata, growth becomes more sensitive to changes in the financial markets and less anchored to ordinary income.

From May to October, continuing a tradition launched in 2011, visitors can pay extra to dig for their own fossils in more recent, less scientifically significant geographical strata.

The kind you might have first met at a 4th of July picnic in a glass Pyrex dish, where guacamole and sour cream mingled with salsa and shredded cheese in slightly slouchy strata.

I thought I wanted a piece of all that; not so much the affluence, but the ease with which he moved through the world with money and social strata no deterrence.

Each stratum, or layer, of our planet tells a story.