Today when you think of tournament you thing of things like sports playoffs or activity that has a group of people competing until only one is left.
Waaaaayyy back in the times of knights and heirs a tournament was a mock battle fought by knights, usually divided into two sides, using blunted or wooden weapons. For these knights one of the major skills they needed to posses was the ability to command their horse using just their knees as their hands would be full of weapons, shields and such. So prior to the “battle” each knight was tested on his horsemanship by guiding his horse through a maze of wooden poles while holding his arms up at shoulder height. If he could “turn” his horse skillfully enough, he could participate. The French word for turn is tourner, and thus the phrase ‘tournament” was born.