As a noun, it is a clear difference between two or more things when they are compared. As a verb, it means to show or notice the differences between things.
From French *contraster* 'to oppose', from Italian *contrastare* 'to withstand, oppose', from Latin *contra* 'against' and *stare* 'to stand'. It originally meant standing against something.
Contrast is what makes differences pop out—black ink on white paper, or a quiet person next to a very loud one. Artists, photographers, and writers all use contrast on purpose to make their work more striking. Even in thinking, we often understand something better by contrasting it with its opposite.
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