blue·ber·ry 
(blbĕr′ē)
(blbĕr′ē)n.
1.
a. Any of various plants of the genus Vaccinium, having white to reddish, urn-shaped or tubular flowers and edible blue to blue-black berries, especially the highbush blueberry and the lowbush blueberry.
b. The fruit of any of these plants.
2. A usually blue-gray spherule that is found in soil and sedimentary rock and is rich in hematite, produced by the weathering of rock or by precipitation from rock by moving groundwater.