rust

rust (http://definr.com/rust)

     adj : of the color of rust [syn: rusty]
     n 1: a red or brown oxide coating on iron or steel caused by the
          action of oxygen and moisture
     2: a reddish-brown discoloration of leaves and stems caused by
        a rust fungus
     3: the formation of reddish-brown ferric oxides on iron by
        low-temperature oxidation in the presence of water [syn: rusting]
     4: any of various fungi causing rust disease in plants [syn: {rust
        fungus}]
     v 1: become destroyed by water, air, or an etching chemical such
          as an acid; "The metal corroded"; "The pipes rusted"
          [syn: corrode]
     2: cause to deteriorate due to the action of water, air, or an
        acid; "The acid corroded the metal"; "The steady dripping
        of water rusted the metal stopper in the sink" [syn: corrode,
         eat]