\Va"ri*a*ble\, a. [L. variabilis: cf. F. variable.]
1. Having the capacity of varying or changing; capable of
   alternation in any manner; changeable; as, variable winds
   or seasons; a variable quantity.
2. Liable to vary; too susceptible of change; mutable;
   fickle; unsteady; inconstant; as, the affections of men
   are variable; passions are variable.
         Lest that thy love prove likewise variable. --Shak.
         His heart, I know, how variable and vain! --Milton.
{Variable exhaust} (Steam Eng.), a blast pipe with an
   adjustable opening.
{Variable quantity} (Math.), a variable.
{Variable stars} (Astron.), fixed stars which vary in their
   brightness, usually in more or less uniform periods.
Syn: Changeable; mutable; fickle; wavering; unsteady;
     versatile; inconstant.

\Va"ri*a*ble\, n.
1. That which is variable; that which varies, or is subject
   to change.
2. (Math.) A quantity which may increase or decrease; a
   quantity which admits of an infinite number of values in
   the same expression; a variable quantity; as, in the
   equation x^{2} - y^{2} = R^{2}, x and y are variables.
3. (Naut.)
   (a) A shifting wind, or one that varies in force.
   (b) pl. Those parts of the sea where a steady wind is not
       expected, especially the parts between the trade-wind
       belts.
{Independent variable} (Math.), that one of two or more
   variables, connected with each other in any way whatever,
   to which changes are supposed to be given at will. Thus,
   in the equation x^{2} - y^{2} = R^{2}, if arbitrary
   changes are supposed to be given to x, then x is the
   independent variable, and y is called a function of x.
   There may be two or more independent variables in an
   equation or problem. Cf. {Dependent variable}, under
   {Dependent}.