A Cosmopolitan is a cocktail made with vodka, triple sec, cranberry juice, and lime juice. Informally referred to as a Cosmo, the Cosmopolitan is usually served in a cocktail glass. For this reason it is often erroneously categorized as a Martini because martinis are also served in cocktail glasses.
A simple recipe is:
Some variations call for orange juice and/or sour mix instead of cranberry juice.
The origin and history of the Cosmopolitan seems to be unknown, but it is sometimes grouped with other cocktails such as margueritas that utilize sour, citrus flavors and sweet syrups as a New Orleans Sour.
See also: list of cocktails