1. A variable referred to in a function, which is not an argument of the function. In lambda-calculus, x is a {bound variable} in the term M = x . T, and a free variable of T. We say x is bound in M and free in T. If T contains a subterm x . U then x is rebound in this term. This nested, inner binding of x is said to "shadow" the outer binding. Occurrences of x in U are free occurrences of the new x. Variables bound at the top level of a program are technically free variables within the terms to which they are bound but are often treated specially because they can be compiled as fixed addresses. Similarly, an identifier bound to a recursive function is also technically a free variable within its own body but is treated specially. A closed term is one containing no free variables. See also closure, lambda lifting, scope. 2. In logic, a variable which is not quantified (see quantifier).

1. A bound variable or formal argument in a function definition is replaced by the actual argument when the function is applied. In the lambda abstraction x . M x is the bound variable. However, x is a free variable of the term M when M is considered on its own. M is the scope of the binding of x. 2. In logic a bound variable is a quantified variable. See quantifier.

In statistics, an exchangeable sequence of random variables (also sometimes interchangeable) is a sequence X1, X2, X3, ... (which may be finitely or infinitely long) whose joint probability distribution does not change when the positions in the sequence in which finitely many of them appear are altered.

In mathematical analysis and its applications, a function of several real variables or real multivariate function is a function with more than one argument, with all arguments being real variables. This concept extends the idea of a function of a real variable to several variables.

<programming> In object-oriented programming, a class suitable to be instantiated, as opposed to an {abstract class}. (1995-05-01)

Critical variables are defined, for example in thermodynamics, in terms of the values of variables at the critical point.

Classical Cepheids (also known as Population I Cepheids, Type I Cepheids, or Delta Cepheid variables) are a type of Cepheid variable star. They are population I variable stars that exhibit regular radial pulsations with periods of a few days to a few weeks and visual amplitudes from a few tenths of a magnitude to about 2 magnitudes.

Class War is an anarchist group and newspaper established by Ian Bone and others in 1983 in the United Kingdom. An incarnation of Class War was briefly registered as a political party for the purposes of fighting the 2015 United Kingdom general election.