LSJ
(Εὔἱος EM 391.15, cf. Lat. Euhius), ὁ, name of Bacchus, from the cry εὐαἵ, εὐοἱ, in lyr. passages, S. OT 211, E. Ba. 157, Ecphantid. 3, etc. ; Εὔιος, = Βάκχος, E. Ba. 566, 579.
εὔιος, ον, as Adj., Bacchic, πῦρ S. Ant. 964; τελεταί E. Ba. 238; ἀγάλματα Id. Tr. 451 (troch.).
Liddell-Scott-Jones, Greek-English Lexicon (9th ed., 1940)