in geometry and analytics, is a term applied by mathematicians to such quantities as are considered in a variable or changeable state, either increasing or decreasing. Thus the abscissas and ordinates of an ellipse, or other curve line, are variable quantities; because they vary or change their magnitude together, the one at the same time with the other. But some quantities may be variable by themselves alone, or while those connected with them are constant: as the abscissa of a parallelogram, whose ordinates may be considered as all equal, and therefore constant; also the diameter of a circle, and the parameter of a conic section, are constant, while their abscissas are variable. See Fluxions, Encycl.