whats the prefix of bayou

Bayou is the root word; it has no prefix.

It was originally a Choctaw word.

If you are learning grammar, please learn how to spell it, too.

The prefix of a word is a word part that comes before the root word and changes its meaning. In the case of the word "bayou," there is no specific prefix. The word "bayou" is actually a loanword from the Louisiana French language, where it refers to a marshy outlet of a lake or river. Since it does not have a prefix, the term "bayou" is considered a root word in the English language.