Any of numerous usually cloudy and rounded spots or patches of a colour or shade different from their background. (Merriam – Webster)
Mark with spots or rounded patches. (Oxford Dictionaries)
To mark or become marked with spots or patches of a different colour; mottle. (Collins Dictionary)
Covered with spots of colour that are lighter or darker than the main colour, or covered with areas of light and darkness. (Cambridge Dictionary)
Do you have a Dapple?
What are the Coat Patterns of the Dapple Dachschund?