Concertina

n.

1.

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.

Noun	1.	concertina - coiled barbed wire used as an obstacle
	2.	concertina - free-reed instrument played like an accordion by pushing its ends together to force air through the reeds
Verb	1.	concertina - collapse like a concertina

collapse