Flips are a type of cocktail made with a distilled spirit, egg and sugar, shaken with ice and strained into a glass. They are similar to Egg Nogs but while Egg Nogs contain milk or cream, Flips don't.
The term was first used in 1695 to describe a mixture of beer, rum, and sugar, heated with a red-hot iron. The iron caused the drink to froth, and this frothing (or "flipping") was where the style of cocktail got its name. Over time, eggs were added and the proportion of sugar increased, the beer was eliminated, and the drink ceased to be served hot.