This is a chemical reaction where a substance loses electrons. In the case of rusting, iron undergoes oxidation to form iron oxide (rust).
Corrosion: This refers to the destruction or deterioration of materials through chemical reactions. Rusting is an example of corrosion where iron deteriorates into iron oxide.
Hydroxide Ion: This is a negatively charged ion made of oxygen and hydrogen (OH-). It plays a role in many chemical reactions including the formation of rust.