A name given to Tāvatimsa, 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 immoveable (Masakkasāro vuccati osakkana parisakkanābhāvena ghanasāratāya ca Sinerupabbarājā), and Tāvatimsa came to be known as Masakkasāra because it was built on Sineru.