Small lake located in a former meander loop of a river or stream channel.
It is generally formed as a river cuts through a meander neck to shorten its course, blocks off the old channel, and then migrates away from the lake. If only one loop is cut off, the lake is crescent-shaped; if more than one loop is cut off, the lake is serpentine (winding). Eventually, oxbow lakes silt up to form marshes and finally meander scars.