1. formal dances held for high school students, typically at the end of the school year
Usage: plural of prom
2. promenade concerts, especially classical music concerts where some audience members stand
Usage: British; informal abbreviation

Examples

• Many high schools hold their proms in May or June.
• She bought a beautiful dress for one of the spring proms.
• The students spent months planning their senior proms.
• Tickets for the proms at Royal Albert Hall sold out quickly.
• He attended several proms during the classical music season.
• The BBC Proms feature world-class orchestras every summer.