# Constant

noun
• algebra
a value that does not change or vary in a mathematical expression or equation.

## Description

A constant is a value that does not change or vary in a mathematical expression or equation. It is the opposite of a variable, which can take on different values. Constants can be numbers, symbols, or even functions that remain unchanged throughout a given problem or context.

For example, in the equation , and are constants, while and are variables. The number is the coefficient of the variable , and is a constant term.

Constants can also be symbols that represent specific values, such as (approximately ), which is the ratio of a circle’s circumference to its diameter, or (approximately ), the base of the natural logarithm.

## Related Terms

A variable is a symbol that represents an unknown or indeterminant quantity. Variables can represent numbers, vectors, or other mathematical objects, depending on the context.

A coefficient is a numerical or constant quantity placed before and multiplying the variable in an algebraic expression.

A function is a mathematical relationship between two sets, called the domain and the codomain, in which each element in the domain corresponds to exactly one element in the codomain. Functions are often represented by equations, graphs, or tables and can model real-world scenarios or abstract concepts.