Gin is a type of alcoholic drink with a high amount of alcohol in it, usually about 35-50% alcohol by volume. It was invented in the Netherlands in the 17th century, and soon became very popular in England. This became a problem when many people drank themselves to death, because gin was cheap to make and contained so much alcohol.
Gin is flavored with juniper berries. Today, gin is usually a dry liquor, which means that it is not very sweet. Gin is also very popular in cocktails - two of the most common of these are the Gin & Tonic (gin mixed with tonic water) and the martini (gin mixed with vermouth, usually with an olive added). Gin is still one of the most popular liquors to this day.