The E horizon is an eluvial horizon, which is a mineral horizon that has lost silicate clay, iron and aluminum. It refers to a layer of soil in the ground.
The E horizon is present in the upper part of the soil. It is located above the B horizon and beneath an O or an A horizon. It's present in forested areas and contains a lighter color than its surrounding horizons and also contains less organic matter. The E horizon is washed off various minerals by percolating water. When this occurs, sand and silt particles remain, and it's these particles that are responsible for its light color.