straightedge

American  

[streyt-ej] / ˈstreɪtˌɛdʒ /

noun

1. a bar or strip of wood, plastic, or metal having at least one long edge of sufficiently reliable straightness for use in drawing or testing straight lines, plane surfaces, etc.

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straightedge British  

/ ˈstreɪtˌɛdʒ /

noun

1. a stiff strip of wood or metal that has one edge straight and true and is used for ruling and testing straight lines

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Other Word Forms

• straightedged adjective

Etymology

Origin of straightedge

First recorded in 1805–15; straight + edge

Example Sentences

And though the forms are simple, straightedge and mostly quadrilateral, they’re handled in ways that hint at 3D perspective.

From Washington Post

Hunter is as straightedge as they come, but he’s, er, a difficult child.

From Washington Post

In those days, proving a mathematical theorem was often as simple as drawing an elegant picture; the tools of ancient Greek mathematics weren’t pencil and paper—they were a straightedge and compasses.

From Literature

A straightedge can be used to extend a line segment in any direction, and a compass can be used to draw a circle with any radius from the chosen center.

From Scientific American

Check your wall surface using a straightedge to make sure it’s flat.

From Seattle Times