“A *register that is implicitly specified by one-address format instructions and is used to contain the results of an operation performed by the *ALU. It can normally be one of the inputs to the ALU, thus the results of a number of successive operations may be built up—hence the name. In addition to holding results, the accumulator commonly has the ability to perform the various *shift and circular shift instructions. It may be part of the *processor status word.” (Fair Use ODCS)