Folding is the process of bending, creasing or otherwise bringing parts of a material or structure into closer contact to change its shape or function. The term applies across many fields: from the deliberate art of paper folding to the formation of mountain ranges, from the compacting of garments to the self-assembly of biological molecules. In each context, folding trades geometric change against material limits such as flexibility, thickness and durability.

Common forms and distinguishing features

Notable categories include:

  • Craft and design: origami and simple household folding (clothes, towels) use creases to create stable shapes.
  • Engineering: hinges, living hinges and articulated linkages enable repeatable folding for furniture, bicycles and foldable electronics.
  • Geology: rock strata fold under tectonic stress to produce anticlines and synclines over long time scales.
  • Biology and chemistry: protein folding and membrane folding are driven by molecular interactions to produce functional three‑dimensional forms.

Folds may be reversible (elastic) or permanent (plastic); they create stress concentrations and often require design features—rounded radii, reinforcing layers or controlled crease lines—to avoid failure.

History and development

Human interest in folding spans millennia. Paper folding matured into the art of origami in East Asia and later became a global practice used in education and design. In engineering, foldable structures evolved with advances in materials and precision hinges, enabling portable furniture and modern folding smartphones. Scientific study of folding—especially in proteins and geology—has developed as observational and computational tools improved.

Folding is important because it can compact large surface areas into small volumes, create complex three‑dimensional forms from two‑dimensional materials, and enable functionality through shape change. Understanding the mechanics and limitations of folding helps designers, geoscientists and biologists anticipate behavior and create resilient solutions.