trigonometry

IPA/ˌtrɪɡəˈnɒmətri/
IPA/ˌtrɪɡəˈnɑːmətri/

trigonometry — noun

1. a branch of mathematics that studies how the angles and side lengths of triangle

1.nounB2
Definition

a branch of mathematics that studies how the angles and side lengths of triangles are connected, often used to calculate distances or heights that are difficult to measure directly

Example

Sumin found trigonometry difficult at first but improved after practising the formulas every day.

personal experience + practice collocation

The surveyor used trigonometry to estimate the height of the bridge across the river.

used + noun to [verb] — purpose structure

Common collocations
  • trigonometry class
  • trigonometry problem
  • trigonometry formula
  • trigonometry homework
  • study trigonometry
  • learn trigonometry
  • use trigonometry

Usage Note

Commonly used as an uncountable noun; you study trigonometry as a subject, not 'a trigonometry'. Frequently abbreviated informally to trig in spoken English (e.g., 'I have a trig test tomorrow').

Common Mistakes

I enrolled in a trigonometry.
I enrolled in a trigonometry course.
trigonometry is uncountable and cannot directly follow 'a'.

Word family

  • trigonometric
    adjectiveB2
  • trigonometrical
    adjectiveC1
  • trig
    nounB2

Synonym discussion

Sense: noun/1

Trigonometry, geometry, algebra, and calculus are the main branches of mathematics taught at secondary school and university level. Geometry (B1) studies the properties and relationships of shapes, points, lines, and surfaces in space — it is the broadest of the four and forms the foundation for trigonometry. Algebra (B1) deals with symbols and the rules for manipulating them to solve equations; its focus is abstract relationships rather than spatial figures. Trigonometry is a specialised subfield of geometry that focuses specifically on triangles and the mathematical functions (sine, cosine, tangent) that describe the ratios of their sides. Calculus (C1) goes further by studying how quantities change and accumulate, using derivatives and integrals. For example, you would use geometry to calculate the area of a circle, algebra to solve for an unknown value in an equation, trigonometry to find the height of a building using a measured angle, and calculus to model the rate at which a population grows.

geometry ↗algebra ↗calculus ↗

Common collocations

Nouns

  • trigonometry class
  • trigonometry problem
  • trigonometry formula
  • trigonometry homework
  • trigonometry exam
  • trigonometry textbook

Phrases

  • study trigonometry
  • learn trigonometry
  • do trigonometry
  • take trigonometry
  • use trigonometry

Prepositions

  • in trigonometry
  • of trigonometry

Etymology

GreekLatinEnglish

Comes from Greek trigōnon 'triangle' (from tri- 'three' + gōnia 'angle') and -metria 'measurement'. The word was formed in Latin as trigonometria and entered English in the early 1600s.

First known use

1614

1614, in the meaning defined above