Imagine you're playing a game with a lot of other people, like a big tournament. A knockout tournament is a type of game where if you lose once, you're out of the game completely. It's like a game of tag - if you get tagged, you have to sit out for the rest of the game.
So let's say there are 8 players in this tournament. The first round, there will be 4 matchups, and the winners of those matchups move on to the next round. The losers are out of the game.
In the next round, there will be 2 matchups with the 4 remaining players. The winners move on to the final round, and the losers are out of the game.
In the final round, the two remaining players face each other in a matchup to see who will be the champion. The winner of this matchup is the only player left standing and they are declared the champion!
So basically, in a knockout tournament, you can't afford to make mistakes because if you lose even once, you're out of the game. It's a really exciting and intense way to play a game or host a tournament!