(strata)
1.
A ~ of society is a group of people in it who are similar in their education, income, or social status. (FORMAL)
It was an enormous task that affected every ~ of society...
N-COUNT: usu with supp
2.
Strata are different layers of rock. (TECHNICAL)
Contained within the rock strata is evidence that the region was intensely dry 15,000 years ago.
N-COUNT: usu pl