[rust] n [ME, fr. OE rust; akin to OE read red--more at red] (bef. 12c) 1 a: the reddish brittle coating formed on iron esp. when chemically attacked by moist air and composed essentially of hydrated ferric oxide b: a comparable coating produced on a metal other than iron by corrosion c: something resembling rust: accretion
2: corrosive or injurious influence or effect
3: any of numerous destructive diseases of plants produced by fungi (order Uredinales) and characterized by usu. reddish brown pustular lesions; also: a fungus causing this
4: a strong reddish brown
[2]rust vi (13c) 1: to form rust: become oxidized "iron ~s"
2: to degenerate esp. from inaction, lack of use, or passage of time "most men would ... have allowed their f aculties to ~ --T. B. Macaulay"
3: to become reddish brown as if with rust "the leaves slowly ~ed"
4: to be affected with a rust fungus ~ vt 1: to cause (a metal) to form rust "keep up your bright swords, for the dew will ~ them --Shak."
2: to impair or corrode by or as if by time, inactivity, or deleterious use
3: to cause to become reddish brown: turn the color of rust