Flatten

Flatten is a verb meaning to make something flat, level, or smooth by reducing height, thickness, or irregularities. It can also mean to compress or erase raised features. The term is used across disciplines to describe a transition from a more complex form to a simpler, more uniform one.

In physical contexts, flattening involves pressing or shaving away bumps to create a level surface. In geometry and computer graphics, flattening describes transforming a curved or three-dimensional surface to a two-dimensional plane or single layer, often by projection or unwrapping.

In computing and data processing, flattening refers to collapsing nested structures into a single sequence or table. Examples include converting multi-dimensional arrays or nested lists into a flat list, or denormalizing hierarchical data for analysis or export. Flattening is a common step in data transformation and loading workflows.

In imaging and document workflows, flattening often means merging multiple layers into one final image or page for output. In mapping and 3D modeling, it can refer to projecting three-dimensional information onto a two-dimensional plane or base surface. The concept of flattening shares the core idea of removing complexity by making elements level, uniform, or easily usable.