Noun
The act of varying; a partial change in the form, position, state, or qualities of a thing; modification; alternation; mutation; diversity; deviation; as, a variation of color in different lights; a variation in size; variation of language.
Extent to which a thing varies; amount of departure from a position or state; amount or rate of change.
Change of termination of words, as in declension, conjugation, derivation, etc.
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.
One of the different arrangements which can be made of any number of quantities taking a certain number of them together.
Source: Webster's dictionaryWestern civilization presents one of the most difficult tasks for historical analysis, because it is not yet finished, because we are a part of it and lack perspective, and because it presents considerable variation from our pattern of historical change. Carroll Quigley
Evolution, thus, is merely contingent on certain processes articulated by Darwin: variation and selection. No longer is a fixed object transformed, as in transformational evolution, but an entirely new start is, so to speak, made in every generation. Ernst Mayr
Uncontrolled variation is the enemy of quality. W. Edwards Deming
One [method] is by a Watch to keep time exactly. But, by reason of the motion of the Ship, the Variation of Heat and Cold, Wet and Dry, and the Difference of Gravity in different Latitudes, such a watch hath not yet been made. Isaac Newton
Variation does not mean evolution. If an artist varies his mode of expression this only means that he has changed his manner of thinking, and in changing, it might be for the better or it might be for the worse. Pablo Picasso
The variation in the value of money, however great, makes no difference in the rate of profits;... David Ricardo