Definition of iron mole in English:
iron mole
noun
rare
A spot or stain on cloth, paper, etc., caused by iron rust or ink containing iron salts.
Origin
Late 16th century; earliest use found in John Lyly (1554–1606), writer and playwright. From iron + mole.
Pronunciation
iron mole
/ˌʌɪən ˈməʊl/