In geometry, a diagonal is a line segment joining two vertices of a polygon or polyhedron, when those vertices are not on the same edge. Informally, any sloping line is called diagonal.

May 14, 2026 · The meaning of DIAGONAL is joining two vertices of a rectilinear figure that are nonadjacent or two vertices of a polyhedral figure that are not in the same face.

A line segment joining one corner to another but is not an edge is called a diagonal. In other words, a diagonal is a line that connects the opposite vertices of a polygon.

A diagonal is made out of a straight line that's set at an angle instead of straight up or across. If you picture a square and draw a line connecting the opposite corners, that’s a diagonal line.

DIAGONAL definition: 1. A diagonal line is straight and sloping, not horizontal or vertical, for example joining two…. Learn more.

Find out the length of the square's diagonal with our diagonal of a square calculator. Check out below how to find the diagonal of a square formula, or simply give our tool a try - you won't be disappointed.

A diagonal is a line segment connecting the opposite vertices or the non-adjacent vertices of a polygon. Learn about the diagonals of polygons, examples, & more.

A diagonal is a straight line that connects two non-adjacent corners (vertices) in a polygon. In simpler terms, it's a line that goes across a shape from one corner to another corner that isn't right next to it.

1. a. connecting two nonadjacent angles or vertices of a polygon or polyhedron: a diagonal line. b. extending from one edge of a solid figure to an opposite edge: a diagonal plane. 2. having an oblique …

In geometry, a diagonal is a straight line that joins two opposite corners in a flat four-sided shape such as a square. Mark five points an equal distance apart along the diagonals. Collins COBUILD …