(1):

(n.) A dark, crystalline, igneous rock, chiefly pyroxene with labradorite.

(2):

(n.) A dark-colored, basic, igneous rock, composed essentially of pyroxene and a triclinic feldspar with magnetic iron. By many authors it is considered equivalent to a coarse-grained basalt.

(3):

(n.) Any dark, igneous rock composed chiefly of silicates of iron and magnesium with some feldspar.

(4):

(n.) Diabase.

(5):

(n.) Coarse-grained basalt.