Dictionary Definition:
opaśá m. (fr. upa-√śī), that on which any one rests, a cushion, pillow RV.ix, 71, 1 ; x, 85, 8 AV. ix, 3, 8 ; xiv, 1, 8
• top-knot, plume (perhaps for avapaśa, √paś)
• (am), n. a support, stay, pillar RV. i, 173, 6 ; viii, 14, 5