e-folding length

e-folding length

[¦ē ¦fōld·iŋ ‚leŋkth]
(physics)
The distance over which the amplitude of any exponentially varying quantity increases or decreases by a factor of e (2.718 …).
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.