accordion vs melodeon

accordion

noun
  • A box-shaped musical instrument with means of keys and buttons, whose tones are generated by play of the wind from a squeezed bellows upon free metallic reeds. 

  • A set of items (concepts, links, or otherwise) that can be packed and unpacked cognitively, or their representation as a set of virtual objects. 

  • A vertical list of items that can be individually expanded and collapsed to reveal their contents. 

verb
  • To fold up, in the manner of an accordion 

melodeon

noun
  • An accordion where the melody-side keyboard is limited to the notes of diatonic scales in a small number of keys. 

  • A music hall. 

  • A type of reed organ with a single keyboard. 

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