third dimension

noun

1. the additional dimension by which a solid object is distinguished from a planar projection of itself or from any planar object.
2. something that heightens the reality, vividness, or significance of a factual account, sequence of happenings, etc.: The illustrations added a third dimension to the story.

noun

1. the additional dimension by which a solid object may be distinguished from a two-dimensional drawing or picture of it or from any planar object