a dark coal that burns easily with a smoky flame yielding pitch or tar: also called soft coal
A type of coal with a high percentage of volatile matter that burns with a smoky yellow flame. Also called soft coal .
A soft type of coal that burns with a smoky, yellow flame. Bituminous coal is the most abundant form of coal. It has a high sulfur content, and when burned, gives off sulfurous compounds that contribute to air pollution and acid rain.