A technical knockout (TKO), or stoppage, is declared when the referee or official ring physician decides during a round that a fighter cannot safely continue the match for any reason, without the need for an intervening count.
A KO is abbreviation of Knock Out. A knockout can occur when a boxer hit and go to the canvas and is not moving and the referee may either count to ten, or simply look at boxer and say, “He’s not getting up”, either way it’s a KO.