The traditional Songkran activity of making merit at a temple is commonly called tam bun in Thai.
Tam bun means “making merit,” a broad expression for religiously meaningful actions intended to generate merit. During Songkran, people may visit temples, give food or other offerings, listen to Buddhist teachings, release animals, or participate in communal ceremonies. The exact custom varies by locality and family.
Making merit is one of the quieter dimensions of Songkran and can be overshadowed by street water celebrations. It helps explain why the festival is more than a recreational water event: the New Year period links renewal with generosity, religious practice, and respect for family members.
Tam bun is a general Buddhist cultural expression rather than a term exclusive to Songkran. It can describe merit-making at many other times of year, including temple festivals, birthdays, funerals, and other important life events.