smoothing iron vs straightener

smoothing iron

noun
  • A heated appliance that is used to smooth clothing and other items after washing and (usually, partially) drying. 

straightener

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

  • A prearranged fight to settle a dispute. 

  • A bribe. 

  • Anyone or anything which straightens. 

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