In usage in the United States, a bayou  is a body of water typically found in a flat, low-lying area, and can be either an extremely slow-moving stream or river (often with a poorly defined shoreline), or a marshy lake or wetland. The term bayou can also refer to a creek whose current reverses daily due to tides and which contains brackish water highly conducive to fish life and plankton. Bayous are commonly found in the Gulf Coast region of the southern United States, notably the Mississippi River Delta, with the states of Louisiana and Texas being famous for them. A bayou is frequently an anabranch or minor braid of a braided channel that is moving much more slowly than the mainstem, often becoming boggy and stagnant. Though fauna varies by region, many bayous are home to crawfish, certain species of shrimp, other shellfish, catfish, frogs, toads, American alligators, American crocodiles, herons, turtles, spoonbills, snakes, leeches, and many other species.
The word entered American English via Louisiana French in Louisiana and is thought to originate from the Choctaw word "bayuk", which means "small stream". The first settlements of Bayou Teche, and other bayous, were by the Cajuns, and that is why bayous are associated with Cajun culture.
An alternative spelling, "buyou", has also been used, as in "Pine Buyou", used in a description by Congress in 1833 of Arkansas Territory.
The term Bayou Country is most closely associated with Cajun and Creole cultural groups derived from French settlers and stretching along the Gulf Coast from Houston, Texas to Mobile, Alabama and picking back up in South Florida around the Everglades with its center in New Orleans, Louisiana.
Houston has the nickname "Bayou City". As of 2016"bye-you" is the most common pronunciation, while a few use "bye-oh", although that pronunciation is declining.