operand

An operand is a value or quantity that an operator acts upon. In mathematics and computer science, expressions are built from operands connected by operators. For example, in the arithmetic expression 3 + 4, the numbers 3 and 4 are operands and + is the operator. In programming languages, operands may be literals, variables, or subexpressions and may themselves be results of prior computations.

Operators are categorized by how many operands they require: unary operators take a single operand (for example -x or !y), binary operators take two operands (a + b, x && y), and ternary operators take three operands (the conditional operator a ? b : c). The same operator may have different meanings depending on the operands and the context.

In computer architecture and assembly language, an operand is a data item supplied to an instruction. Common operand forms include immediate operands (constant values embedded in the instruction), register operands (data held in processor registers), and memory operands (locations in main memory). Some architectures support more complex addressing modes that designate where an operand is located or how it is computed.

Semantics and evaluation: The language defines the order in which operands are evaluated and how expressions are reduced, via rules such as precedence and associativity. Some languages guarantee a particular evaluation order, while others describe it as unspecified or allow optimization, subject to preserving side effects. Understanding operands helps clarify what an expression computes and how a program manipulates data.