Definition of "concertina"

concertina

/ˌkɒnsəˈtiːnə/

noun
plural concertinas
1. (music) 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.
  Quotations
  That concertina was a wonder in its way. The handles that was on it first was wore out long ago, and he'd made new ones of braided rope yarn. And the bellows was patched in more places than a cranberry picker's overalls.
  1913, Joseph C. Lincoln, chapter 8, in Mr. Pratt's Patients
2. Something resembling a concertina, such as a folded book, a bus door or a set of picture frames that are folded together.
3. Coiled barbed wire for use as an obstacle.
4. A type of booklet label, consisting of up to 32 pages of booklet as an insert.
verb
third-person singular simple present concertinas, present participle concertinaing, simple past and past participle concertinaed
1. to become compressed into a shape reminiscent of a concertina
  Quotations
  Millions of years ago the mica schists surrounding the old Brandberg West Mine became folded and concertinaed by enormous horizontal pressures.
  2012, Amy Schoeman, Skeleton Coast, page ii
2. to be drawn closer and farther apart repeatedly, or up and down, as if situated on a working concertina's folds
  Quotations
  This resulted in some fragmentation of the line as the boats in some cases closed to just 50 metres as they concertinaed in and out of sight of each other.
  2007, David W Cameron, 25 April 1915: The Day the Anzac Legend Was Born, page 36