n. [ Cf. F. variabilité. ] 1. The quality or state of being variable; variableness. [ 1913 Webster ]

2. (Biol.) The power possessed by living organisms, both animal and vegetable, of adapting themselves to modifications or changes in their environment, thus possibly giving rise to ultimate variation of structure or function. [ 1913 Webster ]

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. [ 1913 Webster ]

2. Liable to vary; too susceptible of change; mutable; fickle; unsteady; inconstant; as, the affections of men are variable; passions are variable. [ 1913 Webster ]

Lest that thy love prove likewise variable. Shak. [ 1913 Webster ]

His heart, I know, how variable and vain! Milton. [ 1913 Webster ]

Variable exhaust (Steam Eng.), a blast pipe with an adjustable opening. --
Variable quantity (Math.), a variable. --
Variable-rate mortgage (Finance), a mortgage whose percentage interest rate varies depending on some agreed standard, such as the prime rate; -- used often in financing the purchase of a home. Such a mortgage usually has a lower initial interest rate than a fixed-rate mortgage, and this permits buyers of a home to finance the purchase a house of higher price than would be possible with a fixed-rate loan. --
Variable stars (Astron.), fixed stars which vary in their brightness, usually in more or less uniform periods. [ 1913 Webster ]

Syn. -- Changeable; mutable; fickle; wavering; unsteady; versatile; inconstant. [ 1913 Webster ]

n. 1. That which is variable; that which varies, or is subject to change. [ 1913 Webster ]

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 x2 - y2 = R2, x and y are variables. [ 1913 Webster ]

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. [ 1913 Webster ]

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 x2 - y2 = R2, 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. [ 1913 Webster ]

n. The quality or state of being variable; variability. James i. 17. [ 1913 Webster ]

adv. In a variable manner. [ 1913 Webster ]

n. [ L. variantia. ] 1. The quality or state of being variant; change of condition; variation. [ 1913 Webster ]

2. Difference that produces dispute or controversy; disagreement; dissension; discord; dispute; quarrel. [ 1913 Webster ]

That which is the strength of their amity shall prove the immediate author of their variance. Shak. [ 1913 Webster ]

3. (Law) A disagreement or difference between two parts of the same legal proceeding, which, to be effectual, ought to agree, -- as between the writ and the declaration, or between the allegation and the proof. Bouvier. [ 1913 Webster ]

4. (Statistics) The expected value of the square of the deviation from the mean of a randomly distributed variable; the second moment about the mean. This is also the square of the standard deviation. [ PJC ]

At variance, in disagreement; in a state of dissension or controversy; at enmity. “What cause brought him so soon at variance with himself?” Milton. [ 1913 Webster ]

a. [ L. varians, p. pr. of variare to change: cf. F. variant. See Vary. ] 1. Varying in form, character, or the like; variable; different; diverse. [ 1913 Webster ]

2. Changeable; changing; fickle. [ Obs. ] [ 1913 Webster ]

He is so variant, he abit [ abides ] nowhere. Chaucer. [ 1913 Webster ]

n. [ Cf. F. variante. ] Something which differs in form from another thing, though really the same; as, a variant from a type in natural history; a variant of a story or a word. [ 1913 Webster ]

v. t. & i. [ L. variatus, p. p. of variare. See Vary. ] To alter; to make different; to vary. [ 1913 Webster ]

n. [ OE. variatioun, F. variation, L. variatio. See Vary. ] 1. The act of varying; a partial change in the form, position, state, or qualities of a thing; modification; alteration; mutation; diversity; deviation; as, a variation of color in different lights; a variation in size; variation of language. [ 1913 Webster ]

The essences of things are conceived not capable of any such variation. Locke. [ 1913 Webster ]

2. Extent to which a thing varies; amount of departure from a position or state; amount or rate of change. [ 1913 Webster ]

3. (Gram.) Change of termination of words, as in declension, conjugation, derivation, etc. [ 1913 Webster ]

4. (Mus.) Repetition of a theme or melody with fanciful embellishments or modifications, in time, tune, or harmony, or sometimes change of key; the presentation of a musical thought in new and varied aspects, yet so that the essential features of the original shall still preserve their identity. [ 1913 Webster ]

5. (Alg.) One of the different arrangements which can be made of any number of quantities taking a certain number of them together. [ 1913 Webster ]

Annual variation (Astron.), the yearly change in the right ascension or declination of a star, produced by the combined effects of the precession of the equinoxes and the proper motion of the star. --
Calculus of variations. See under Calculus. --
Variation compass. See under Compass. --
Variation of the moon (Astron.), an inequality of the moon's motion, depending on the angular distance of the moon from the sun. It is greater at the octants, and zero at the quadratures. --
Variation of the needle (Geog. & Naut.), the angle included between the true and magnetic meridians of a place; the deviation of the direction of a magnetic needle from the true north and south line; -- called also declination of the needle. [ 1913 Webster ]

Syn. -- Change; vicissitude; variety; deviation. [ 1913 Webster ]