upavāsa
keeping a prescribed day, fasting, self-denial, abstaining from enjoyments uposatha*; used extensively in BSk. in meaning of uposatha, e.g. at Avs.i.338, Avs.i.339; Divy.398 in phrase aṣṭânga-samanvāgataṃ upavāsaṃ upavasati] AN.v.40 (? uncertain; vv.ll. upāsaka, ovāpavāssa, yopavāsa); Ja.vi.508; Snp-a.199 (in expln. of uposatha).
fr. upa + vas, see upavasati