What does "final four" mean?

The four regional champions of the NCAA Division I tournament, one of whom will become the national champion.

What is a synonym for "final four"?

Common synonyms include: semis.

noun, slang

noun, slang ·Moderate ·College level

Noun

1
The four regional champions of the NCAA Division I tournament, one of whom will become the national champion. US, informal
2
The final two rounds of the NCAA Division I tournament. US, informal
3
An appearance in the Final Four. US, informal
"These two teams have an amazing number of Final Fours between them."
4
The final round of the continent-wide Euroleague club basketball competition, featuring four teams with one becoming champion. Europe
5
The semifinal round, or an appearance in it generally. Philippines, informal

"These two teams have an amazing number of Final Fours between them."