1. of or relating to Euclid or the geometry based on his axioms and postulates, in which parallel lines never meet and the angles of a triangle sum to 180 degrees
Usage: also spelled Euclidean; mathematics

Examples

• In euclidian geometry, the shortest distance between two points is a straight line.
• Most high school students learn euclidian geometry before studying non-euclidian spaces.
• The euclidian plane is the foundation of classical mathematics.
• Euclidian space assumes that parallel lines will never intersect.
• Modern physics sometimes requires non-euclidian geometry to describe the universe.