n.
Pronunciation: ' r ə st
Function: noun
Etymology: Middle English, from Old English r ū st; akin to Old English r ē ad red ― more at RED
Date: before 12th century
1 a : the reddish brittle coating formed on iron especially 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 usually reddish-brown pustular lesions also : a fungus causing this
4 : a strong reddish brown