From Proto-Italic *wolwō, from Proto-Indo-European *welH- (“to turn, wind, round”).
Cognate with Ancient Greek ἐλύω (elúō, “to roll around”), εἰλύω (eilúō, “to enfold”), εἴλω (eílō, “to roll up, pack close”), ἑλίσσω (helíssō, “to turn round, to roll”), ἕλιξ (hélix), Albanian valle (“circle dance”), Old Armenian գելում (gelum), Old English wielwan, wealwian (“to roll”). Compare Latin vulgus. More at wallow.