A "kilo" is a unit of measurement in the metric system, representing one thousand units of something. It is commonly used to measure weight, where one kilogram (kg) equals 1,000 grams. The prefix "kilo-" comes from the Greek word "chilioi," meaning "thousand." Kilos are widely used around the world, especially in countries that follow the metric system, such as France, Germany, and Japan. In everyday life, you might encounter kilos when buying food, like fruits or vegetables, or when measuring body weight.