Concise Pali-English Dictionary by A.P. Buddhadatta Mahathera
āpatti:[f.] getting into; an ecclesiastical offence.
Buddhist Dictionary of Pali Proper Names by G P Malalasekera
Āpatti:āpatti.-A section of the Vinaya Pitaka,the fourth chapter of the Parivāra. Vin.v.91ff.
āpatti Vagga.-The twenty-fifth chapter of the Catukka Nipāta of the Anguttara Nikāya,containing ten suttas on various subjects. A.ii.239-46.
1. āpatti Sutta.-Ananda informs the Buddha at Ghositārāma in Kosambī,that Bāhiya’s efforts to bring about dissension in the Order had not been suppressed because Anuruddha,being Bāhiya’s colleague,did not want to interfere. The Buddha tells him that they should not depend on Anuruddha for interference in disputes,for he was by temperament unfitted for such action. He then proceeds to discourse to Ananda on the four probable reasons for a monk being desirous of creating dissension (A.ii.239f).
2. āpatti Sutta.-Deals with the four kinds of fears produced by transgressions,involving either being taken in the act and punished or having to confess guilt and receive punishment. A.ii.240-3.