54. Chā ṭṭha+ṭṭhamāti

Chasaddā pūraṇatthe ṭṭha+ṭṭhamā. Channaṃ pūraṇo chaṭṭho, chaṭṭhamo. Itthiyaṃ chaṭṭhī, chaṭṭhamī. ‘‘Catutthadutiyesve+saṃ tatiyapaṭhamā’’ti nipātanā pūraṇatthe dvito tiyo dvissa du ca, ticatūhi tissa a, tiya+tthā ca yathākkamaṃ, dutiyo tatiyo, catuttho.