accordion vs concertina

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 

concertina

noun
  • A musical instrument, like the various accordions, that is a member of the free-reed family of musical instruments, typically having buttons on both ends. 

  • A type of booklet label, consisting of up to 32 pages of booklet as an insert. 

  • Something resembling a concertina, such as a folded book, a bus door or a set of picture frames that are folded together. 

  • Coiled barbed wire for use as an obstacle. 

verb
  • to be drawn closer and farther apart repeatedly, or up and down, as if situated on a working concertina's folds 

  • to become compressed into a shape reminiscent of a concertina 

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