A fisherman's bend.
fisherman's bend 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 kind of knot
fisherman's bend definition by American Heritage Dictionary
A knot used to secure the end of a line to a ring or spar, made by two turns with the end passed back under both.