A fold made by bringing two edges of paper together, usually marked by a dashed line in diagrams. The valley fold creates a crease that bends the paper toward you, shaping the initial structure of many models.

A fold where the paper is bent away from you, forming a raised ridge. The mountain fold is a basic move that often comes right after a valley fold in sequence.

A set of basic preliminary folds resulting in a central shape, like the 'bird base,' used as a starting point for more complex models.

An origami form designed to move, such as a jumping frog or flapping bird. These models often use action folds to produce simple motion.

Lightweight paper, often square and colored on one side, specifically designed for crisp creases and easy shaping in origami.

The process of tucking one part of paper inside or under another, useful for creating hidden flaps or locking pieces together in modular designs.

A square base is created by folding two valley folds and two mountain folds, forming a symmetrical shape that serves as the foundation for many classic models.

A squash fold involves opening a flap and pressing it flat, resulting in a new layer or detail. Common in flowers or animal heads, this fold adds dimension and shape.