grog (n.) Look up grog at Dictionary.com
alcoholic drink diluted with water, 1749, supposedly a reference to Old Grog, nickname of Edward Vernon (1684-1757), British admiral who wore a grogram (q.v.) cloak and who in August 1740 ordered his sailors' rum to be diluted. George Washington's older half-brother Lawrence served under Vernon in the Carribean and renamed the family's Hunting Creek Plantation in Virginia for him in 1740, calling it Mount Vernon.