I. rust 1 /rʌst/ BrE AmE noun [uncountable]
[ Language: Old English ]
1 . the reddish-brown substance that forms on iron or steel when it gets wet ⇨ rusty :
There were large patches of rust on the car.
2 . a plant disease that causes reddish-brown spots
II. rust 2 BrE AmE verb [intransitive and transitive]
to become covered with rust, or to make something become covered in rust:
The metal had begun to rust.
The gate was old and badly rusted.
rust away phrasal verb
to be gradually destroyed by rust:
The blades of the swords have rusted away.