Postseason (noun)

1. The period following the end of the regular season in a sport, during which teams compete for the championship.
2. The period following the end of the regular season in which teams compete for the championship in a sport.

Origin:

From post- + season.

Examples:

1. The Red Sox are currently in the midst of the postseason and are looking to win the World Series.
2. His team made it to the postseason for the first time in years.
3. The postseason is upon us and the excitement is building.
4. They are the best team in the league and they are going to the postseason.
5. The team is trying to win the championship in the post season.