An outhaul is a line which is part of the running rigging of a sailboat, used to extend a sail and control the shape of the curve of the foot of the sail. It runs from the clew (the back corner of the sail) to the end of the boom. The line is pulled taut to the appropriate tension to provide the desired shape to the foot and then secured to a clea... Found on http://en.wikipedia.org/wiki/Outhaul
The line used to pull a sail toward the end of the boom, or the grommet at the corner of the sail to which that line attaches. Found on http://www.glen-l.com/resources/glossary.html
Usually a line or tackle, an outhaul is used to pull the clew of the mainsail towards the end of the boom, thus tightening the foot of the sail. Found on http://www.sailinglinks.com/glossary.htm