zythum, i, n., = ζῦθος,
a kind of malt-liquor among the Egyptians, Plin. 22, 25, 82, § 164; Col. 10, 116; Dig. 33, 6, 9 praef.
·noun A kind of ancient malt beverage; a liquor made from malt and wheat. ...
Webster's Dictionary of the English Language