Accumulator :-

• The term "accumulator" is used in a wide variety of noncomputing applications and activities, such as electrical engineering (an energy storage device such as a rechargeable battery or ultracapacitor), hydraulics (a mechanical energy storage device), in stock trading (a contract or agreement), and even in gambling (a parlay bet).

• An accumulator is a register for short-term, intermediate storage of arithmetic and logic data in a computer's CPU (central processing unit).

• The term "accumulator" is rarely used in reference to contemporary CPUs, having been replaced around the turn of the millennium by the term "register." In a modern computers, any register can function as an accumulator.

• The most elementary use for an accumulator is adding a sequence of numbers. The numerical value in the accumulator increases as each number is added, exactly as it happens in a simple desktop calculator (but much faster, of course). Once the sum has been determined, it is written to the main memory or to another register.