What is the meaning of rust?

noun

• A red or brown oxide coating on iron or steel caused by the action of oxygen and moisture.
• A plant disease that produces a reddish-brown discoloration of leaves and stems; caused by various rust fungi.
• The formation of reddish-brown ferric oxides on iron by low-temperature oxidation in the presence of water.
  • synonyms: rusting
• Any of various fungi causing rust disease in plants.
  • synonyms: rust fungus

verb

• Become destroyed by water, air, or a corrosive such as an acid.
  • usage: "The metal corroded"; "The pipes rusted"
  • synonyms: corrode
• Cause to deteriorate due to the action of water, air, or an acid.
  • usage: "The acid corroded the metal"; "The steady dripping of water rusted the metal stopper in the sink"
  • synonyms: corrode, eat
• Become coated with oxide.

adjective

• Of the brown color of rust.
  • synonyms: rusty, rust-brown