constante

Constante is a term used across disciplines to denote a fixed value that does not change within a given context. It contrasts with variables, which can take different values depending on inputs, conditions, or time. The idea of a constant helps define laws, formulas, and models by supplying stable reference quantities.

In mathematics, a constant is a specific number or a fixed quantity that does not vary with the arguments of a function. Examples include familiar numbers like pi (π) and Euler's number (e), as well as constants that appear in formulas, such as a constant term that does not depend on variables. Some constants also arise as constants of integration, denoting undetermined fixed values in solutions.

In physics and related sciences, constants are quantities whose values are universal within a theory or experimental context. Well-known physical constants include the speed of light in vacuum (c), the gravitational constant (G), and Planck's constant (h). Many constants are determined experimentally and reported with uncertainties; organizations such as CODATA publish standardized values used in calculations.

In computing, const is a keyword or modifier used to declare values that cannot be reassigned after initialization. This immutability can improve program reliability and readability, and it varies in syntax across programming languages, with examples in languages like C, Java, and JavaScript.

The notion extends to other fields, where a constant may describe any invariant quantity, such as a fixed rate or a dimensionless quantity like the fine-structure constant (α). Overall, constants provide stable reference points essential for reasoning, measurement, and computation.