| a dark-red, crystalline, water-insoluble solid, Fe2O3, occurring naturally, as hematite and rust, or synthesized: used chiefly as a pigment, as a mordant, as a coating for magnetic recording tape, and in the manufacture of polishing compounds. |
| ferric oxide n. A dark red compound, Fe2O3, occurring naturally as hematite ore and rust and used in pigments and metal polishes and on magnetic tapes. |
