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

Derived Forms

• right-angled
  adjective

Etymology

Origin of right angle

Middle English word dating back to 1350–1400

Example Sentences

Will the robots in his specially built factory ever line up at precisely the right angle?

From The Wall Street Journal • May 17, 2026

Just as vehicles cannot navigate sudden right angle turns at speed, light does not travel efficiently through sharp bends.

From Science Daily • Feb. 24, 2026

Water must be flowing, skies must be clear and the setting sun must hit at the right angle.

From Los Angeles Times • Feb. 12, 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

“You have to play in a boxed area and you have to stand at a right angle to the wind,” he said proudly.

From "The Kite Runner" by Khaled Hosseini