from The American Heritage® Dictionary of the English Language, 4th Edition
- n. See E layer.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. a region of the ionosphere (from 50 to 90 miles up) that reflects radio waves of medium length
After Oliver Heaviside (1850-1925), British physicist.(American Heritage® Dictionary of the English Language, Fourth Edition)