farewell party; send-off party
A gathering held to wish someone well before they leave for a new endeavor, such as a new job, study abroad, or a sports tournament.
We held a farewell party for a friend who is going to study abroad next month.
motivational rally; pep rally
A gathering to boost morale before a competition or challenging undertaking, often with speeches and cheers.
A motivational rally was held for the athletes competing in the national tournament.