/ ˌkɒnsəˈtiːnə; NAmE ˌkɑːnsərˈt-/ noun , verb
■ noun
a musical instrument like a small accordion , that you hold in both hands. You press the ends together and pull them apart to produce sounds.
■ verb
( con·cer·tina·ing , con·cer·tinaed , con·cer·tinaed ) [ v ] ( BrE ) to fold up like a concertina :
The truck crashed into the tree and concertinaed.
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WORD ORIGIN
mid 19th cent.: from concert + -ina .