In the United States and Canada, a prom, short for promenade, is a formal (black tie) dance, or gathering of high school students.
A lot of high school "last" lately.
Tomorrow night, Robert's last prom.
Tux - check.
Corsage - check.
Limo - check.
Dinner Reservations - check.
Memories - in the making.
Mom's million of photos - to follow.