'bayou' originates from Louisiana French, specifically the word 'bayou', which in turn comes from Choctaw 'bayuk' (or similar forms) where 'bayuk' meant 'small creek' or 'slow-moving stream'.

'bayou' changed from the Choctaw word 'bayuk' into Louisiana French 'bayou', and eventually entered English as the modern word 'bayou' via contact in the Gulf Coast region.

Initially it meant 'small creek' or 'stream' in the source languages; over time it came to refer specifically to the slow-moving, often marshy waterways characteristic of the southern U.S., especially Louisiana.