triangle
triangle — noun
1. A two-dimensional shape that is made by connecting three points with straight li
A two-dimensional shape that is made by connecting three points with straight lines. Every triangle has three sides and three corners.
The maths teacher asked Hao to measure each angle of the triangle on the board.
collocation: angle of a triangle / measure an angle
A red triangle on a road sign usually means drivers should slow down.
common use: triangle on road signs
Ada folded the paper so that it formed a perfect triangle.
Sophia drew a triangle with three sides of different lengths for homework.
- three-sided figure
a longer, more descriptive phrase; less common in everyday speech
文法句型
triangle + of
用法筆記
In mathematics, triangles are named by their side lengths (equilateral, isosceles, scalene) or by their angles (acute, right-angled, obtuse).
常見錯誤
2. An object, area, or piece of material whose outline looks roughly like a three-s
An object, area, or piece of material whose outline looks roughly like a three-sided figure, even though it may not be a mathematically perfect one.
Elena cut the sandwich into a triangle and packed it for her lunch.
collocation: cut + [food] + into a triangle
Anjali grows herbs in a small triangle of land at the back of the garden.
collocation: a triangle of [land/space/area]
The street market spilled out into a triangle where two roads met.
Layla folded the napkin into a triangle and set it beside each dinner plate.
文法句型
a triangle of + noun
用法筆記
Common in descriptions of geography, urban spaces, and food preparation. 'A triangle of X' is a frequent pattern.
常見錯誤
3. A small percussion instrument crafted from a slender steel rod that is curved in
A small percussion instrument crafted from a slender steel rod that is curved into a three-sided open form. A string holds the instrument while the player taps it with a thin metal beater, producing a clear, high-pitched ringing sound.
In the school orchestra, Jude was responsible for playing the triangle.
collocation: play the triangle (instrument)
The triangle gives a bright clear ring when tapped with a thin metal rod.
sound description: high, clear note
The percussionist struck the triangle once at the very end of the song.
The music teacher showed Sophia how to hold the triangle by its nylon string.
- percussion instrument
the broader category, not a direct synonym
文法句型
play the triangle
strike the triangle
用法筆記
When referring to the instrument as a general type, native speakers say 'the triangle' (e.g., 'She plays the triangle').
常見錯誤
4. A flat drawing aid cut into a right-angled triangular form and crafted from plas
A flat drawing aid cut into a right-angled triangular form and crafted from plastic or metal. Students and designers use it to draw neat lines and to check or mark specific angles on paper.
Lisa used a triangle to draw parallel lines across her graph paper.
collocation: use a triangle to draw [lines]
The architect kept a clear plastic triangle inside her pencil case.
With a triangle and a ruler, Erik sketched a roof with a steep slope.
Tariro checked the angle of her line using a clear plastic triangle.
- set square
more common in British English; refers to the same tool
文法句型
use a triangle
draw with a triangle
用法筆記
Also called a 'set square' in British English. 'Triangle' is the more common term in American English classrooms.
常見錯誤
5. A wooden or plastic rack shaped like a triangle, used to pack the balls tightly
A wooden or plastic rack shaped like a triangle, used to pack the balls tightly against one another before the opening shot in pool, snooker, or billiards.
The player placed the triangle over the balls before starting the game of pool.
collocation: place the triangle over the balls
Tamar lifted the triangle away after the balls were set for the break shot.
collocation: lift the triangle away / set the balls
The wooden triangle held all fifteen pool balls in a tight formation.
The attendant handed Layla a triangle and waited for her to rack the balls.
- rack
shorter and more common among experienced players; refers to any shaped frame, not just triangles
文法句型
place the triangle over [the balls]
triangle + for [game]
用法筆記
Also called a 'rack' or 'pool rack'. 'Triangle' is the most descriptive term for beginners because it emphasises the shape.
常見錯誤
6. A set of circumstances where three people are emotionally linked with each other
A set of circumstances where three people are emotionally linked with each other — most often, one person has romantic ties with two others, leading to difficult emotions and decisions.
The film tells the story of a love triangle between two brothers and one woman.
collocation: love triangle between [three people]
Nadia wanted to avoid being caught in a triangle with her two best friends.
collocation: caught in a triangle
A messy love triangle at work made everyone in the office uncomfortable.
The novel traces a love triangle that lasts more than twenty years.
- love triangle
the full standard phrase; 'triangle' alone is a shortened form
- complicated relationship
broader and less specific; can describe any difficult relationship, not just three-way involvement
文法句型
a love triangle + between [people]
用法筆記
Almost always appears as 'love triangle' rather than 'triangle' alone. 'Triangle' by itself can sound vague, so the full phrase is strongly preferred in both speech and writing.