What is a "mule" in cocktail terminology?

A "mule" in cocktail terminology specifically refers to a drink that features vodka, ginger beer, and lime juice. The classic example of a mule is the Moscow Mule, which is traditionally served in a copper mug. The combination of ginger beer's spiciness, the tartness of lime, and the smoothness of vodka creates a refreshing and balanced cocktail. This drink has gained popularity due to its invigorating flavor profile and unique presentation.

Other options describe different types of cocktails but do not accurately represent the definition of a mule. A cocktail made with whiskey does not fit this definition, nor does a mix of rum and cola or a fruity blended cocktail. Each of those drinks has its distinct characteristics and ingredients, highlighting the importance of understanding cocktail terminology in bartending.