Waisak utawi Waisaka (Pali; Sanskrit: Vaiśākha वैशाख) inggih punika rahina suci agama Buddha. Rahina Waisak taler ketah kawastanin Visakah Puja utawi Buddha Purnima ring India, Saga Dewa ring Tibet, Vesak ring Malaysia miwah Singapura, Visakha Bucharing Thailand, miwah Vesak ring Sri Lanka. Wasta puniki kaambil saking basa Pali "Wesakha", sané ring gilirannyané makaitan sareng "Waishakha" saking basa Sanskerta, sané madué artos wastan bulan ring kalénder Buddhist. Ring makudang-kudang genah taler kasengguh "rahina Buddha".[1]