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]

Source: The Collaborative International Dictionary of English v.0.48
 

Rubus fruticosus

Source: WordNet (r) 2.0
 

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; R. villosus and R. Canadensis are the high blackberry and low blackberry of the United States. There are also other kinds.

Source: Webster's Revised Unabridged Dictionary (1913)