The Collaborative International Dictionary of English v.0.48:

Blackberry \Black"ber*ry\ (bl[a^]k"b[e^]r*r[y^]), n. [OE.
   blakberye, AS. bl[ae]cberie; bl[ae]c black + berie berry.]
   The fruit of several species of bramble (Rubus); also, the
   plant itself. Rubus fruticosus is the blackberry of
   England; Rubus villosus and Rubus Canadensis are the high
   blackberry and low blackberry of the United States. There are
   also other kinds.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Rubus fruticosus
    n 1: the true blackberry of Europe as well as any of numerous
         varieties having sweet edible black or dark purple berries
         [syn: true blackberry, Rubus fruticosus]