The Collaborative International Dictionary of English v.0.48:

Salal-berry \Sal"al-ber`ry\, n. [Probably of American Indian
   origin.] (Bot.)
   The edible fruit of the Gaultheria Shallon, an ericaceous
   shrub found from California northwards. The berries are about
   the size of a common grape and of a dark purple color.
   [1913 Webster]