صَدْوٌ as an inf. n. of which the verb is صَدَا: see 2 in art. صدى, in two places.

صَدْوٌ as a subst. A certain liquid poison which is applied upon arrow-heads, or spear-heads, or the like, resembling the blood of the [serpent called] أَسْوَد. (M, TA.)