cast iron vs flatiron

cast iron

noun
  • A hard and brittle, but strong, alloy of iron, carbon, and silicon, formed by casting in a mould. 

adj
  • Inflexible or without exception. 

  • Made of cast iron. 

  • Durable; tough; resilient. 

flatiron

noun
  • A simple iron (for pressing laundry) which is heated on a stove. 

  • A steeply sloping triangular landform created by the differential erosion of a steeply dipping, erosion-resistant layer of rock overlying softer strata. 

  • a quadrilateral with two parallel sides, one of which is very short, and whose non-parallel sides are longer than either parallel side. 

  • A pair of metal tongs with heated ceramic plates used for straightening hair. 

adj
  • Having a flatiron shape. 

How often have the words cast iron and flatiron occurred in a corpus of books? (source: Google Ngram Viewer )