Vodka is one of the world's most popular distilled beverages. It is a clear liquid containing water, ethanol purified by distillation from a fermented substance such as potatoes, grain or sugar beet molasses, and an insignificant amount of other substances: impurities and possibly flavourings. Except for various types of flavourings, vodka is a colourless liquid.

Vodka usually has an alcohol content of 35% to 50% by volume. The classic Russian, Lithuanian and Polish vodka is 40% (80 proof). This can be attributed to the Russian standards for vodka production introduced in 1894 by Alexander III from research undertaken by the Russian chemist Dmitri Mendeleev. According to the Vodka Museum in Moscow, Mendeleev found the perfect percentage to be 38. However, since spirits in his time were taxed on their strength, the percentage was rounded up to 40 to simplify the tax computation. At strengths less than this, vodka drunk neat (not mixed with other liquids) can taste "watery": above this strength, the taste of vodka can have more "burn". Some governments set a minimum alcohol content for a spirit to be called "vodka". For example, the European Union sets a minimum of 37.5% alcohol by volume.

Although vodka is traditionally drunk neat in Eastern European and Nordic countries of the "Vodka Belt", its popularity elsewhere owes much to its usefulness in cocktails and other mixed drinks, such as the Bloody Mary, the Screwdriver, the vodka tonic, and the vodka martini.