An AA battery—also called a double A or Mignon (French for "cute") battery—is a standard size single cell cylindrical dry battery. The IEC system calls it size R6, and ANSI calls it size 15.
AA batteries are common in portable electronic devices. An AA battery is composed of a single electrochemical cell that may be either a primary battery (disposable) or a rechargeable battery. The exact terminal voltage and capacity of an AA size battery depends on cell chemistry. AA batteries account for over 50% of general battery sales.
The AA battery size was standardized by the American National Standards Institute (ANSI) in 1947, but it had been used in flashlights and electrical novelties for some time before formal standardization. ANSI and IEC Battery nomenclature gives several designations for cells in this size, depending on cell features and chemistry.