right angle

American  

noun

• right angles
  plural

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°.

---

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

---

right angle Scientific  

/ rīt /

1. An angle having a measure of 90°.

---

right angle Cultural  

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

---

Other Word Forms

Derived Forms

• right-angled
  adjective

Inflected Forms

Nouns

• right angles
  plural

Etymology

Origin of right angle

Middle English word dating back to 1350–1400

Example Sentences

See Examples For:

right angle

With scarcely a right angle, and therefore no fixed point for my eyes to rest, the interior kept giving me differing impressions.

From The Wall Street Journal ● Mar. 6, 2026

Viewed at the right angle, the piece resembles a giant eye.

From Los Angeles Times ● Feb. 2, 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

They had been gold at first, but now I saw how they shone iridescently— like the rainbow colors you see on a soap bubble if you look at it from the right angle.

From "Dragonwings" by Laurence Yep