Plooien

Plooien is a Dutch term that functions as both a noun and a verb. As a noun, plooi (plural plooien) denotes a fold, crease or pleat in fabric, leather, paper or other flexible material. As a verb, plooien means to create such folds, to pleat, or to fold material to form ridges.

In textiles and fashion, plooien shape garments, provide structure, or add decorative detail. Pleats can be permanent, achieved by stitching, pressing, or heat-setting, or temporary, formed by tucks and folds. Common types include knife pleats, box pleats, inverted pleats and accordion pleats, each yielding a different outward profile and flow of fabric.

In geology, plooien describes folds in rock layers produced by tectonic compression. These folds can range from broad, open flexures to tight structures such as anticlines and synclines, recording the deformation history of the crust.

Beyond textiles and geology, the concept of plooien appears in crafts and art, including paper folding and garment construction, where controlled folds create texture, volume, and movement.