A festival held by Asoka in honour of the Buddha when Māhakāḷa created for him a figure of the Buddha. The festival lasted for seven days (Mhv.v.94).
The Mahāvaṃsa Ṭīkā explains it by saying that the king fasted for seven days, standing gazing at the figure with unblinking eyes. However, even at the time of the Ṭīkā there seems to have been uncertainty regarding the meaning of the word. See MT.209 f.