'Concertina' definitions:

Definition of 'concertina'

From: WordNet
noun
Coiled barbed wire used as an obstacle
noun
Free-reed instrument played like an accordion by pushing its ends together to force air through the reeds
verb
Collapse like a concertina

Definition of 'Concertina'

From: GCIDE
  • Concertina \Con`cer*ti"na\, n. [From It. concerto a concert.] A small musical instrument on the principle of the accordion. It is a small elastic box, or bellows, having free reeds on the inside, and keys and handles on the outside of each of the two hexagonal heads. [1913 Webster]