Variable

Variable may refer to:

Variable (computer science), a symbolic name associated with a value and whose associated value may be changed
Variable (mathematics), a symbol that represents a quantity in a mathematical expression, as used in many sciences

Mathematics

Propositional variable, taking the value true or false in mathematical logic
Random variable, a variable in statistics whose value depends on random events
- Categorical variable, taking one of a finite number of values in a statistical problem, such as the head or tail result of a tossed coin
- Independent and identically distributed random variables, statistically independent and having the same probability distribution
Fluent (mathematics), a time-varying quantity as coined by Isaac Newton in his early calculus
State variable, used to describe the mathematical "state" of a dynamical system
Slack variable, inserted to transform an inequality constraint in an optimization problem into an equality
Dependent and independent variables, a variable classified according to whether or not it depends for its value on another variable of interest
Free variables and bound variables, restricted or otherwise to a specified set of values, such as through a logical quantifier
Complex variable, the argument or value of a function of a complex number in complex analysis

Variable (research), a logical set of attributes
Control variable, a measurable entity which is constant (controlled) and unchanged throughout the course of a scientific experiment
Variable star, a type of astronomical star