boysenberry means: This hybrid blackberry-raspberry mixture has a purple-red colour and tart-sweet taste. (in Cooking Dictionary)

What else does boysenberry mean?

This shrub is usually quite prickly and is a cross between a blackberry from the western North American west. (Rubus ursinus) It is grown for its dark-red to almost black edible fruit. (in Merlin Dictionary)

This is the fruit. (in Merlin Dictionary)