The continuous parallel folding of brochures and similar printed material in an accordion-like fashion, that is with folds alternatively made to the front and back.
The paper is folded two or more times in a parallel direction. Each fold reverses the direction, similar to the bellows of an accordion. Also called a “Z” fold. Often used for items printed on one side only.
Finishing term for two or more parallel folds which open like a concertina. Also called an accordion fold.