a level of material, such as a type of rock or gas, that is different from the material above or below it, or a thin sheet of a substance
A thick layer of clay lies over the sandstone.
There was a thin layer of oil on the surface of the water.
We stripped several layers of paint off the door.
Each layer of the atmosphere serves a unique purpose.
The cake had multiple layers of frosting.
Geologists study the Earth's layers to understand its history.
An onion consists of concentric layers.
