Origin: Latin suffix -al
Diagonal has 10 different meanings across 3 categories:
Noun · Adjective · Proper Noun
(geometry) a straight line connecting any two vertices of a polygon that are not adjacent
"In a square, drawing a diagonal creates two equal right-angled triangles by connecting opposite corners."
an oblique line of squares of the same color on a checkerboard
"the bishop moves on the diagonals"
(mathematics) a set of entries in a square matrix running diagonally either from the upper left to lower right entry or running from the upper right to lower left entry
"In linear algebra, calculating the determinant often requires evaluating the product of all diagonal entries in a square matrix."
A line joining non-adjacent vertices of a polygon.
"In a square, drawing a diagonal connects two opposite corners that are not next to each other."
In plain English: A diagonal is a straight line that connects two opposite corners of a shape without going along its edges.
"The diagonal across the rectangle was longer than either side."
connecting two nonadjacent corners of a plane figure or any two corners of a solid that are not in the same face
"a diagonal line across the page"
Joining two nonadjacent vertices (of a polygon or polyhedron).
"In a square, drawing a line from one corner to the opposite corner creates a diagonal that joins two nonadjacent vertices."
In plain English: Diagonal means going from one corner to another across something instead of along its straight edges.
"The diagonal line on the poster caught my eye immediately."
Usage: Use this adjective to describe lines connecting opposite corners in geometric shapes like squares, rectangles, and polygons. It specifically refers to the slanted path between two points that are not directly across from each other on an edge or face.
A city and town in Iowa.
"Diagonal is a small unincorporated community located in Jasper County, Iowa."
The word "diagonal" entered English via Middle French and Latin, ultimately tracing back to Ancient Greek. It originally described a line running across or from one angle to another within a shape.