an organism of the kingdom Fungi lacking chlorophyll and feeding on organic matter; ranging from unicellular or multicellular organisms to spore-bearing syncytia | A strong reddish brown color. |
| any of various fungi causing rust disease in plants |
| the formation of reddish-brown ferric oxides on iron by low-temperature oxidation in the presence of water |
| a plant disease that produces a reddish-brown discoloration of leaves and stems; caused by various rust fungi |
| a red or brown oxide coating on iron or steel caused by the action of oxygen and moisture |