right angle

American  

noun

1. the angle formed by two radii of a circle that are drawn to the extremities of an arc equal to one quarter of the circle; the angle formed by two perpendicular lines that intersect; an angle of 90°.

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right angle British  

noun

1. the angle between two radii of a circle that cut off on the circumference an arc equal in length to one quarter of the circumference; an angle of 90° or π/2 radians

2. perpendicular or perpendicularly

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right angle Scientific  

/ rīt /

1. An angle having a measure of 90°.

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right angle Cultural  

1. An angle measuring ninety degrees, formed by the intersection of two perpendicular lines. (Compare acute angle and obtuse angle.)

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Other Word Forms

• right-angled adjective

Etymology

Origin of right angle

Middle English word dating back to 1350–1400

Example Sentences

But it also has an amazing property: If two lines on the Earth’s surface meet at a right angle in reality, they will still do so on the map.

From Slate • Jan. 21, 2026

A key concept in this area is the "Schweikart triangle," a special type of triangle with one right angle and two zero angles.

From Science Daily • Jan. 7, 2026

We’ve all witnessed a photo shoot where the subjects keep checking to see if they have the right angle and pose to share online, once they blur out any imperfections.

From The Wall Street Journal • Nov. 11, 2025

It goes up and over the top rather than around the side, travelling at a right angle to the carousel-like path we normally find.

From Space Scoop • May 6, 2025

It was badly bent, with one leg twisted at a right angle to the others.

From "Earthquake Terror" by Peg Kehret