Contrast is a noun and verb with multiple meanings:
1. The state of being strikingly different from something else in juxtaposition or close association.
2. In visual perception, the difference in luminance or color that makes an object distinguishable.
3. In photography and display technology, the ratio of the luminance of the brightest color to that of the darkest color.
4. In rhetoric, a literary device that shows the difference between two things.
5. In statistics, a method for comparing means between groups.