A name given to Tāvatiṃsa, the abode of Vāsava (Sakka) (J.v.167; vi. 272, 289, 400; VvA.350).

The scholiast explains (J.v.168; vi. 272) that Masakkasāra is really the name of Mount Sineru, so called because it is immovable (Masakkasāro vuccati osakkana parisakkanābhāvena ghanasāratāya ca Sinerupabbarājā), and Tāvatiṃsa came to be known as Masakkasāra because it was built on Sineru.