"Double" refers to the concept of multiplying a number or quantity by two. For example, if you have 3 apples and you double that amount, you will have 6 apples. This concept is commonly used in mathematics and everyday situations, such as cooking or shopping, where quantities need to be increased. In addition to numbers, "double" can also describe anything that comes in pairs or twofold. For instance, a double bed is designed to accommodate two people, and a double feature in a movie theater shows two films back-to-back. This idea of pairing or duplication is prevalent in various aspects of life.