1) a baby delivered during a prom dance and tossed in the trash.
2) a baby that results from post-prom activities.
1997: Melissa Drexler, who slipped into the bathroom at her senior prom, delivered a 6-lb. 6-oz. baby boy and tossed him in the trash basket with the soiled paper towels in time to get back to the party. She asked the disk jockey to play her favorite Metallica song and danced with her boyfriend. A student told a reporter later, "She seemed to be enjoying herself for just delivering a prom baby."