Sotāpannassa aṅgāni: the 'characteristic qualities of a Stream-winner' are 4: unshakable faith towards the Enlightened One, unshakable faith towards the Doctrine, unshakable faith towards the Order, and perfect morality. Explained in S. LV, I, D. 33, in S. XLVII, 8 and in Netti-ppakaraṇa these 4 qualities are called Sotāpattiyaṅga (q.v.).

Buddhist Dictionary, Manual of Buddhist Terms and Doctrines, by NYANATILOKA MAHATHERA