1. concertina - Noun
2. concertina - Verb
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.
Source: Webster's dictionaryWhen I was at school I used to scream in trains, in those concertina things between the carriages. I used to try to be so good that sometimes I couldn't bear it any more. Jane Birkin
German or Anglo-German concertinas were regarded as a lower-class instrument, and English concertina had an air of bourgeois respectability. Source: Internet
Chemnitzer concertina main Various German concertina systems share common construction features and core button layout. Source: Internet
Concertina main When push-points are absent, but there is not enough space to use sidewinding because of lateral constraints, such as in tunnels, snakes rely on concertina locomotion. Source: Internet
His 1844 patent for what he called a “concertina” also featured the ability to easily tune the reeds from the outside with a simple tool. Source: Internet
In general, snakes will use a modified form of concertina locomotion on smooth branches, but will laterally undulate if contact points are available. Source: Internet