Short for 'semifinals', the round before the final round in a sports competition.
Semis are exciting because the winners go to the final round.
Examples:
The team won the semis and will play in the final.
The semis are tomorrow, and I hope our team wins.
In the semis, the players try their best to win.
The semis are like a big party for the teams.
The semis are the most important games before the final.
The semis are when the best teams play against each other.