2D

Two-dimensional, or 2D, refers to objects or spaces characterized by two independent directions, typically represented by the x- and y-axes. A point in 2D space is given by an ordered pair (x, y) in the Cartesian plane. In mathematics, 2D describes the Euclidean plane, a flat surface that locally resembles a plane; in topology, a 2D manifold is a space where every point has a neighborhood similar to a two-dimensional Euclidean space.

Common 2D shapes include points, lines, polygons, circles, and more complex curves. Transformations such as translation, rotation, and scaling preserve 2D structure, and many problems in geometry and analysis are formulated in two dimensions for simplicity or visualization. 2D can also be described using alternative coordinate systems, such as polar coordinates, which use radius and angle.

2D is contrasted with 3D, which adds depth. In computer graphics and imaging, 2D refers to graphics on a plane, defined by pixels (raster) or mathematical curves (vector). 2D graphics underpin icons, user interfaces, and many games, while 3D graphics introduce depth, perspective, and shading for realistic rendering.

In data and computing, two-dimensional representations include 2D arrays or matrices, and images are commonly stored as 2D grids of pixels (often with multiple channels for color). Historically, the concept of 2D emerged with analytic geometry in the 17th century, enabling algebraic treatment of geometric figures, and has since become foundational in mathematics, science, and digital media.