Liquor (also hard liquor, hard alcohol, spirit, or distilled drink) is an alcoholic drink produced by distillation of grains, fruit, or vegetables that have already gone through alcoholic fermentation. The distillation process purifies the liquid and removes diluting components like water, for the purpose of increasing its proportion of alcohol content (commonly expressed as alcohol by volume, ABV). As liquors contain significantly more alcohol, they are considered 'harder' – in North America, the term hard liquor is used to distinguish distilled alcoholic drinks from non-distilled ones. Liquor (also hard liquor, hard alcohol, spirit, or distilled drink) is an alcoholic drink produced by distillation of grains, fruit, or vegetables that have already gone through alcoholic fermentation. The distillation process purifies the liquid and removes diluting components like water, for the purpose of increasing its proportion of alcohol content (commonly expressed as alcohol by volume, ABV). As liquors contain significantly more alcohol, they are considered 'harder' – in North America, the term hard liquor is used to distinguish distilled alcoholic drinks from non-distilled ones. As examples, this term does not include beverages such as beer, wine, mead, sake, or cider, as they are fermented but not distilled. These all have a relatively low alcohol content, typically less than 15%. Brandy is a liquor produced by the distillation of wine, and has an ABV of over 35%. Other examples of liquors include vodka, baijiu, gin, rum, tequila, mezcal, and whisky. (Also see list of alcoholic drinks, and liquors by national origin.) The term 'spirit' refers to liquor that contains no added sugar and has at least 20% alcohol by volume (ABV). Liquor bottled with added sugar and added flavorings, such as Grand Marnier, Frangelico, and American schnapps, are known instead as liqueurs. Liquor generally has an alcohol concentration higher than 30%. Beer and wine, which are not distilled, are limited to a maximum alcohol content of about 20% ABV, as most yeasts cannot metabolise when the concentration of alcohol is above this level; as a consequence, fermentation ceases at that point. The origin of 'liquor' and its close relative 'liquid' was the Latin verb liquere, meaning 'to be fluid'. According to the Oxford English Dictionary, an early use of the word in the English language, meaning simply 'a liquid', can be dated to 1225. The first use the OED mentions of its meaning 'a liquid for drinking' occurred in the 14th century. Its use as a term for 'an intoxicating alcoholic drink' appeared in the 16th century. The term 'spirit' in reference to alcohol stems from Middle Eastern alchemy. These alchemists were more concerned with medical elixirs than with transmuting lead into gold. The vapor given off and collected during an alchemical process (as with distillation of alcohol) was called a spirit of the original material. Early evidence of distillation comes from Akkadian tablets dated circa 1200 BC describing perfumery operations, providing textual evidence that an early, primitive form of distillation was known to the Babylonians of ancient Mesopotamia. Early evidence of distillation also comes from alchemists working in Alexandria, Roman Egypt, in the 1st century. Distilled water was described in the 2nd century AD by Alexander of Aphrodisias. Alchemists in Roman Egypt were using a distillation alembic or still device in the 3rd century. Distillation was known in the ancient Indian subcontinent, evident from baked clay retorts and receivers found at Taxila and Charsadda in modern Pakistan, dating back to the early centuries of the Christian era. These 'Gandhara stills' were only capable of producing very weak liquor, as there was no efficient means of collecting the vapors at low heat.