Variation means an instance of change or the rate or magnitude of change. It may refer to

Biology:

• Biodiversity
• Genetic variation, differences within a species
• Variation (genetics), mutations resulting from chromosomal alteration

Physics:

• Magnetic variation, difference between magnetic north and true north, measured as an angle
• Variation (astronomy), any perturbation of the mean motion or orbit of a planet or satellite, particularly of the Moon

Mathematics:

• Bounded variation
• Calculus of variations, in which δf is called the variation of the function f, is a field of mathematics which deals with functions of functions.
• Variance (variation is a misnomer though), in statistics a measure of the spread of a variable

Arts:

• Variation (ballet), solo dance or dance figure *Variation (music), formal technique where material is altered during repetition

Other:

• Direct variation
• Indirect variation
• Variation (game), modifications made to a game by a community of players (as opposed to a central authority)
• Varations (band), French rock band

Variace | Variation | Variación | Variation | Variazione | 変奏曲 | Вариация | Biến tấu | 变奏曲