ccharles wrote:Does this refer to sleeping after sunrise or after dawn?
It's not altogether certain whether it means (1) oversleeping in the morning, (2) taking siestas at noon, or (3) sleeping at any time during the day. But if it means #1, then much like the English expression "to have a lie-in" the word doesn't entail any stipulation as to whether one sleeps until after sunrise or until after dawn.
Khandhānaṃ rāsaṭṭhaṃ, āyatanānaṃ āyatanaṭṭhaṃ,
Dhātūnaṃ suññaṭṭhaṃ, indriyānaṃ adhipatiyaṭṭhaṃ,
Saccānaṃ tathaṭṭhaṃ aviditaṃ karotītipi ‘avijjā’.
It prevents knowing the meaning of heap in the aggregates, the meaning of actuating in the sense-bases, the meaning of voidness in the elements, the meaning of predominance in the faculties, and the meaning of suchness in the truths, thus it is called ‘ignorance’.
(Visuddhimagga XVII. 43)