n (musical instruments) 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.
n Something resembling a concertina, such as a folded book, a bus door or a set of picture frames that are folded together.
n Coiled barbed wire for use as an obstacle.Webster's New Dictionary And Thesaurus, Geddes & Grosset Ltd., New Lanark, Scotland 1990
n A type of booklet label, consisting of up to 32 pages of booklet as an insert.
v to become compressed into a shape reminiscent of a concertina
v to be drawn closer and farther apart repeatedly, or up and down, as if situated on a working concertina's folds