Definition of mold noun from the Oxford Advanced Learner's Dictionary

mold

noun (especially US) (British English, Canadian English mould)
məʊld
 
; moʊld
 
 
1 [countable] a container that you pour a liquid or soft substance into, which then becomes solid in the same shape as the container, for example when it is cooled or cookedA clay mold is used for casting bronze statues.Pour the chocolate into a heart-shaped mold.They broke the mold when they made you (= there is nobody like you).2 [countable, usually singular] a particular style showing the characteristics, attitudes or behaviour that are typical of somebody/somethinga hero in the ‘Superman’ moldHe is cast in a different mold from his predecessor.She doesn't fit (into) the traditional mold of an academic.3 [uncountable, countable] a fine soft green, grey or black substance like fur that grows on old food or on objects that are left in warm wet airThere's mold on the cheese.molds and fungimold growth see also leaf mould
Idioms

break the mold (of something)

to change what people expect from a situation, especially by acting in a dramatic and original way