Bayou \Bay"ou\, n.; pl. {Bayous}. [North Am. Indian bayuk, in F. spelling bayouc, bayouque.] An inlet from the Gulf of Mexico, from a lake, or from a large river, sometimes sluggish, sometimes without perceptible movement except from tide and wind. [Southern U. S.] A dark slender thread of a bayou moves loiteringly northeastward into a swamp of huge cypresses. --G. W. Cable.