rust
Plural
rusts
1
a red or brown oxide coating on iron or steel caused by the action of oxygen and moisture
2
any of various fungi causing rust disease in plants
Synonyms:
3
the formation of reddish-brown ferric oxides on iron by low-temperature oxidation in the presence of water
Synonyms:
4
a plant disease that produces a reddish-brown discoloration of leaves and stems; caused by various rust fungi