bayou [Louisiana Fr.; from Choctaw bayuk=small stream], term used mainly in U.S. Gulf states, especially Louisiana and Mississippi, to describe a stationary or sluggishly moving body of water that was once part of a lake, river, or gulf and is swampy or marshy in nature. Bayou is sometimes used as a synonym for oxbow lake, a former meander in a river valley cut off from that stream.

Teche, Bayou, 125 mi (201 km) long, S La., formed by tributary bayous and flowing SE to the Atchafalaya River near Morgan City. Navigable for more than 100 mi (161 km), it flows through a fertile sugarcane area. Bayou Teche was the setting for Henry Wadsworth Longfellow's Evangeline.

Macon, Bayou, c.145 mi (230 km) long, rising in SE Ark. and flowing S into NE La. to the Tensas River. It was used as a rendezvous by the bandits Frank and Jesse James.