Dappled is an adjective that means marked with spots or rounded patches. If you can picture Bambi's dappled rear, then you are on the right track.
The origins of dappled are a bit mysterious. Its use as an adjective may date from around 1400, from a Middle English word that referred to the markings on an apple, or maybe to gray horses with round blotches that resembled apples. Dappled is usually used to describe markings on a horse or a deer, though photographers also appreciate "the dappled effect of sunlight filtered through leaves."