The Collaborative International Dictionary of English v.0.48:

Avignon berry \A`vignon" ber"ry\ (Bot.)
   The fruit of the Rhamnus infectorius, eand of other species
   of the same genus; -- so called from the city of Avignon, in
   France. It is used by dyers and painters for coloring yellow.
   Called also French berry.
   [1913 Webster]