Rust
Definition 1 of 5
Pro Tip 1/2
Material Specific
Use 'rust' for metals reacting with moisture, mainly iron and steel. The garden tools have started to rust after the rainy season.
Pro Tip 2/2
Visible Damage
'Rust' implies visible deterioration, often seen as an undesirable, damaging process. Check for any rust before buying the second-hand bike.