KO stands for knockout, while TKO stands for a technical knockout. Both terms are rampant in boing. If the opponent is knocked out and is not able to get back up before the referee counts to ten, then the other boxer wins by a knockout.
If the opponent is injured while boxing, and they cannot persevere, it is considered a technical knockout, and the other boxer wins. A victory by a knockout means that the fighter won by knocking out their opponent super hard, causing them to be unconscious.
A technical knockout win means the fight has stopped because the boxer is still conscious but not getting up because he or she is doing nothing to defend themselves.