Term KYBO Definition (Pronounced KAI-bo) slang term for outhouses. It is an acronym that stands for “Keep Your Bowels Open” or “Kleen Your Bowels Out”. Contributor Ferdinand Tretter Score Score of 3 from 1 reviews. How would you rate this item? - - VOTE!! - - 1 Star 2 Star 3 Star 4 Star 5 Star (Best) Click here to report possible copyright violations.