lit. 'fasting', i.e. 'fasting day',

• is the full-moon day,
• the new-moon day,
• and the two days of the first and last moon-quarters.

On full-moon and new-moon days, the Disciplinary Code, the Pātimokkha, is read before the assembled community of monks (bhikkhu), while on the mentioned 4 moon-days many of the faithful lay devotees go to visit the monasteries, and there take upon themselves the observance of the 8 rules (attha-sīla; sikkhāpada). See A.VIII.41ff.