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

They weren’t even sure the video was real when they watched the jar hurtle across their screens at exactly the right angle for the label to spin into focus.

From The Wall Street Journal • Apr. 9, 2026

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

“There’s barely a right angle on the entire property. Everything’s amorphous in shape.”

From Los Angeles Times • Nov. 21, 2025

Holding one of the nails in his right hand, he showed me the right angle.

From "Where the Red Fern Grows" by Wilson Rawls