Definition of cankerfret in US English:

cankerfret

noun

English Regional, East Anglian
rare
  • A corroded surface on metal; especially verdigris on copper. Compare "canker".

Origin

Early 17th century; earliest use found in Edmund Bolton (?1575/5–?1634), antiquary and historian. From canker + fret.

Pronunciation

cankerfret

/ˈkaŋkəfrɛt/