"The word grog refers to a variety of alcoholic beverages. The word originally referred to a drink made with water or "small beer" (a weak beer) and rum, which was introduced into the Royal Navy by British Vice Admiral Edward Vernon (nicknamed "Old Grog" by the sailors) on 21 August 1740. Modern versions of the drink are often made with hot or boiling water, and sometimes include lemon juice, lime juice, cinnamon or sugar to improve the taste. Rum with water, sugar and nutmeg was known as bumboo and was more popular with pirates and merchantmen.

By contrast, in Australia and New Zealand, the word has come to mean any alcoholic drink."

The name "grog" probably came from the nickname of Admiral Vernon, who was known as "Old Grog" because he wore a grogram cloak.