Adder may refer to: AA-12 Adder, a Russian air-to-air missile Adder (electronics), an electronic circuit designed to do addition Adder Technology, a manufacturing company Armstrong Siddeley Adder, a late 1940s British turbojet engine Blackadder, a series of BBC sitcoms Golden Axe: The Revenge of Death Adder, a video game HMS Adder, any of seven ships of the Royal Navy Any of several groups of venomous snakes Common European adder, found in Europe and northern Asia USS Adder, a US submarine See also Addition, a mathematical operation