accordion fold accordion fold /əˈkɔːrdiən foʊld/

noun

1. A continuous parallel folding in an accordion-like fashion, that is with folds alternatively made to the front and back in zig-zag folds.  ( accordion fold , concertina fold , z-fold , zig-zag fold )
   a continuous parallel folding in an accordion-like fashion, that is with folds alternatively made to the front and back in zig-zag folds.
    Seen from above, concertina folds resemble a Z or M or series of zigs and zags.
   Seen from above, concertina folds resemble a Z or M or series of zigs and zags.