senior scream

A tradition in some high schools (and maybe colleges) where at the start of the last trimester/semester of their senior year, they all gather and scream.

Person 1: bro, second trimesters over and third trimester starts tommorow. Are you gonna do the senior scream?

Person 2: duh! Meeting with the rest of the grade after school to scream and celebrate the beginning of the end of high school!!!