- a white, crystalline, water-insoluble powder, BaSO4, used chiefly in the synthesis of pigments, as in paints and printing inks, and, because of its radiopacity, for x-ray diagnosis in medicine.
- A fine white powder used as a pigment and as a contrast medium in x-ray photography of the digestive tract.
- A fine white powder used in making textiles, rubber, and plastic. It is also used in diagnostic imaging of the digestive tract. Barium sulfate occurs in nature as the mineral barite. Chemical formula: BaSO4.