Illustration of triangle
- 1 equilateral
- 2 acute
- 3 obtuse
- 4 scalene
- 5 isosceles
- 6 right triangle
triangle
noun
tri·an·gle
ˈtrī-ˌaŋ-gəl 
1
: a polygon having three sides compare spherical triangle
2
a
: a percussion instrument consisting of a rod of steel bent into the form of a triangle open at one angle and sounded by striking with a small metal rod
b
: a drafting instrument consisting of a thin flat right-angled triangle of wood or plastic with acute angles of 45 degrees or of 30 degrees and 60 degrees
3
: a situation in which one member of a couple is involved in a love affair with a third person
Examples of triangle in a Sentence
She cut the sandwiches into triangles.
Recent Examples on the Web
Their lives are filled with toxic boys, broken families and destructive love-triangles, which threaten their enviable ecosystem.
—
Max Goldbart, Deadline, 4 Dec. 2025
Lola Tung has spent the last few summers at the center of the most culturally significant love triangle since Carrie, Big, and Aidan.
—Rachel Handler, Vulture, 1 Dec. 2025
As if the love triangle wasn't complicated enough!
—Shania Russell, Entertainment Weekly, 30 Nov. 2025
Anne is stuck in a love triangle between the one who got away, Captain Frederick Wentworth (Cosmo Jarvis) and blunt opportunist (and her distant cousin) William Elliot (Henry Golding), who isn't shy about his attempts to seduce Anne or his intentions to inherit the family fortune.
—Andrea Wurzburger, PEOPLE, 29 Nov. 2025
See All Example Sentences for triangle
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Max Goldbart, Deadline, 4 Dec. 2025
Lola Tung has spent the last few summers at the center of the most culturally significant love triangle since Carrie, Big, and Aidan.
—Rachel Handler, Vulture, 1 Dec. 2025
As if the love triangle wasn't complicated enough!
—Shania Russell, Entertainment Weekly, 30 Nov. 2025
Anne is stuck in a love triangle between the one who got away, Captain Frederick Wentworth (Cosmo Jarvis) and blunt opportunist (and her distant cousin) William Elliot (Henry Golding), who isn't shy about his attempts to seduce Anne or his intentions to inherit the family fortune.
—Andrea Wurzburger, PEOPLE, 29 Nov. 2025
See All Example Sentences for triangle
Cite this Entry
“Triangle.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/triangle. Accessed 6 Dec. 2025.
Copy CitationKids Definition
triangle
noun
tri·an·gle
ˈtrī-ˌaŋ-gəl
1
: a figure that has three sides and three angles : a polygon that has three sides
2
: a percussion instrument made of a steel rod bent into a triangle open at one corner which is played by striking with a metal rod
3
: a drafting instrument consisting of a thin flat right-angled triangle
Medical Definition
triangle
noun
tri·an·gle
ˈtrī-ˌaŋ-gəl
: a three-sided region or space and especially an anatomical one see anterior triangle, carotid triangle, femoral triangle, posterior triangle, suboccipital triangle
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