Minyan is the Hebrew term for a Jewish religious quorum traditionally needed for certain public prayers at a bar mitzvah service.
In traditional Jewish law, a minyan consists of ten Jewish adults. Certain parts of communal worship, including Kaddish and some Torah-related prayers, are traditionally recited only when the required quorum is present.
The details of who counts as an adult can differ among Jewish movements. Orthodox communities generally count men over the traditional age, while many Conservative, Reform, and other communities count women and men. Some communities also use different policies for online or hybrid gatherings.
A minyan is not the same thing as the invited audience or the number of guests at a party. A bar or bat mitzvah celebration may have many attendees, but the religious quorum concerns participation in specified communal prayers.