Vodka (Polish: wódka [ˈvutka]; Russian: водка [ˈvotkə]) is a clear distilled alcoholic beverage. Its varieties originated in Poland and Russia. Vodka is composed mainly of water and ethanol but sometimes with traces of impurities and flavourings. Traditionally, it is made by distilling liquid from fermented cereal grains and potatoes since the latter was introduced in Europe in the 18th century. Some modern brands use maize, sugar cane, fruit, honey, and maple sap as the base.

Since the 1890s, standard vodkas have been 40% alcohol by volume (ABV) (80 U.S. proof). The European Union has established a minimum alcohol content of 37.5% for vodka. Vodka in the United States must have a minimum alcohol content of 40%.

Vodka is traditionally drunk "neat" (not mixed with water, ice, or other mixers), and it is often served freezer chilled in the so-called "vodka belt" of Belarus, Estonia, Finland, Iceland, Latvia, Lithuania, Norway, Poland, Russia, Sweden, and Ukraine. It is also used in cocktails and mixed drinks, such as the vodka martini, Cosmopolitan, vodka tonic, screwdriver, greyhound, Black or White Russian, Moscow mule, Bloody Mary, Caesar and Red Bull Vodka.

Since 1960s, the unflavoured Swedish brännvin also came to be called vodka.

The word vodka is a diminutive of the Slavic word voda 'water' (literally, 'little water'): root vod- [water] + -k- (diminutive suffix, among other functions) + -a (ending of feminine gender).

In English literature, the word vodka appeared around the late 18th century. In a book of travels published in English in 1780 (presumably, a translation from German), Johann Gottlieb Georgi correctly explained that "kabak in the Russian language signifies a public house for the common people to drink vodka (a sort of brandy) in". In 1799, William Tooke glossed vodka as "rectified corn-spirits", using the traditional English sense of the word corn to refer to any grain, not just maize. In 1800, the French poet Théophile Gautier glossed it as a "grain liquor" served with meals in Poland (eau-de-vie de grain).

Another possible connection of vodka with water is the name of the medieval alcoholic beverage aqua vitae (Latin, literally, 'water of life'), which is reflected in Polish okowita, Ukrainian оковита, Belarusian акавіта, and Scandinavian akvavit. Whiskey has a similar etymology, from Irish and Scottish Gaelic uisce beatha / uisge-beatha.

People in the area of vodka's probable origin have names for vodka with roots meaning 'to burn': Polish: gorzała; Ukrainian: горілка, romanized: horilka; Belarusian: гарэлка, romanized: harelka; Lithuanian: degtinė; Samogitian: degtėnė is also in use, colloquially and in proverbs; Latvian: degvīns; Finnish: paloviina. In Russian during the 17th and 18th centuries, горящѣе вино or горячее вино (goryashchee vino 'burning wine' or 'hot wine') was widely used. Others languages include German Branntwein, Danish brændevin, Dutch: brandewijn, Swedish: brännvin, and Norwegian: brennevin (although the latter terms refer to any strong alcoholic beverage).