Operand vs. Opcode

Operandnoun

A quantity to which an operator is applied (in $3\; -\; x$, the operands of the subtraction operator are 3 and $x$).

Opcodenoun

(computing) A mnemonic used to refer to a microprocessor instruction in assembly language.

Operandnoun

The symbol, quantity, or thing upon which a mathematical operation is performed; - called also faciend.

Opcodenoun

2010 and the .NET 4 Platform (page 655)

Operandnoun

a quantity upon which a mathematical operation is performed

Opcode

In computing, an opcode (abbreviated from operation code, also known as instruction machine code, instruction code, instruction syllable, instruction parcel or opstring) is the portion of a machine language instruction that specifies the operation to be performed. Beside the opcode itself, most instructions also specify the data they will process, in the form of operands.

Operand

In mathematics an operand is the object of a mathematical operation, i.e., it is the object or quantity that is operated on.