two-dimensional

/ˌtu dɪˈmɛnʃənəl/

Two-dimensional things are flat — they can be measured in length and width, but they have no depth. Geometrical shapes like squares, circles, and polygons are all two-dimensional.

A sheet of paper may seem to be two-dimensional, but because it does have a measurable (if tiny) depth, it's actually three-dimensional. Your dog is also three-dimensional, but a picture of him on your computer screen is two-dimensional. You can also use this mathematical adjective to mean "superficial," or "shallow." A bad guy in a movie might be described as a two-dimensional character, for example, since he seems to have "no depth."

Definitions of two-dimensional

1. adjective

   involving two dimensions
   synonyms: planar

   coplanar

   lying in the same plane

   flat

   having a relatively broad surface in relation to depth or thickness

   placoid, platelike

   as the hard flattened scales of e.g. sharks

   flattened, planate

   having been flattened

   tabular

   flat; like a table in form
2. adjective

   lacking the expected range or depth; not designed to give an illusion or depth
   “a film with two-dimensional characters”

   synonyms: 2-dimensional, flat

   multidimensional

   having or involving or marked by several dimensions or aspects