stag night 
(also stag party)
noun
1British A celebration held for a man shortly before his wedding, attended by his male friends only.The comedy is set around a stag night, a wedding reception, three pubs and a drunken priest with lots of music, memorabilia and fashion from the era....
- You might get married one day and want to have a stag night.
- A bridegroom-to-be was among six men injured on a stag night out when a mini bus crashed on a moorland road.
1.1North American Any party attended by men only.There were hundreds of people, line-ups to get in, and people were coming in for stag parties and birthday parties....
- Hen or stag parties are also widely welcomed in many Blackpool hotels and some of them are even organizing themes events for you.
- Having in the past catered for office weekends, hen and stag parties, and children's parties Fosseys are always open to new ideas.