bayou

noun, plural bay·ous. Chiefly Lower Mississippi Valley and Gulf States.

1. a marshy arm, inlet, or outlet of a lake, river, etc., usually sluggish or stagnant.
2. any of various other often boggy and slow-moving or still bodies of water.

noun

1. (in the southern US) a sluggish marshy tributary of a lake or river

n.

1766, via Louisiana French, from Choctaw bayuk “small stream.”

1. A sluggish, marshy stream connected with a river, lake, or gulf. Bayous are common in the southern United States.

Term used mainly in Louisiana and Mississippi to describe a swampy, slowly moving or stationary body of water that was once part of a lake, river, or gulf.