E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
The name of Sancho Panzas donkey in Cervantes romance of Don Quixote. Bailey derives dapple from the Teutonic dapper (streaked or spotted like a pippin). A dapple-grey horse is one of a light grey shaded with a deper hue; a dapple-bay is a light bay spotted with bay of a deeper colour. (Icelandic, depill, a spot.)