The fourth of the six deva worlds. AN.i.210

Four hundred years of human life are equal to one day of the Tusita world and four thousand years, so reckoned, is the term of life of a deva born in Tusita. AN.i.214 AN.iv.261

Sometimes Sakadāgāmins (e.g., Purāṇa and Isidatta) are born there. AN.iii.348 AN.v.138

It is the rule for all Bodhisattas to be born in Tusita in their last life but one. The inhabitants of Tusita were present at the Mahāsamaya. DN.ii.161