boundary layer definition by Webster's New World
Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio. Used by arrangement with John Wiley & Sons, Inc.
a very thin layer of fluid immediately next to a solid body, that flows more slowly than the rest of the fluid
boundary layer definition by American Heritage Dictionary
The layer of reduced velocity in fluids, such as air and water, that is immediately adjacent to the surface of a solid past which the fluid is flowing.