An assemblage of items that are loosely related. Generally considered to be nearly random in composition. The items grouped together are often odd, uncommon, greatly varied, and/or represent nearly every conceivable combination imaginable.
Example: I ordered a packet of wildflower seeds. It was a "duke's mixture" of flowering plants. There were 45 different kinds of seeds in it, and the only thing they had in common was that they all bloomed.