Alexander Dyce, A General Glossary to Shakespeare's Works

‘rivo!’ “says the drunkard,” 1 HENRY IV., ii. 4. 107. This Bacchanalian exclamation is not uncommon in our old writers; but its origin is quite uncertain: Gifford suggests (not very probably) that it is “corrupted perhaps from the Spanish rio, which is figuratively used for a large quantity of liquor.” Note on Massinger's Works, vol. ii. p. 167, ed. 1813 (In Marlowe's Jew of Malta we find “Hey, Rivo Castiliano!” Works, p. 172, ed. Dyce, 1858 ; and in Day's Law-Trickes, 1608, “Riuo, Ile bee singuler; my royall expence shall run such a circular course,” Sig. F 3 ).