Quad

A four-vertex face, the modeler's preferred polygon.

A quad is a face with four vertices. Quads are the standard working polygon because they subdivide predictably, deform cleanly in animation, and form readable loops across a model. Good topology mostly means well-organized quads.

Related: Tri (Triangle) · N-gon · Edge Flow

These fundamentals are covered hands-on in Blender Geometry Essentials 01, free with a free account.