This meaning refers to a large social dance, often organized near the end of a school year.
They rented formal clothes for the prom.
The school prom will be held in June.
In British usage, a prom can be a concert at which some audience members traditionally stand in an open area.
The orchestra performed at a summer prom.
Thousands listened to the final prom.
This informal British use abbreviates promenade and refers especially to a walkway beside the sea.
We walked along the prom after dinner.
The hotel overlooks the seaside prom.