operand
1. A quantity upon which a mathematical or logical operation is performed.

2. The parts of a machine instruction that specify the objects upon which the operation is to be performed. For instance, in the instruction ADD A,B

A and B are the operands and could be registers in the central processor, or actual values, or addresses of values, or even addresses of addresses of values.

op·er·and / ˈäpəˌrand/ • n. Math. the quantity on which an operation is to be done.