What does trigonometry mean?
Trigonometry is the branch of mathematics that studies the relationships between the angles and sides of triangles. Its best-known tools are the trigonometric functions sine, cosine, and tangent, which allow lengths, angles, and directions to be calculated from limited information. The subject is fundamental to geometry but is also applied in surveying, navigation, astronomy, physics, and engineering. For example, a surveyor can determine a tower’s height by using the angle to its top and the length of its shadow. The word is generally formal and academic, though “trig” is common as an informal abbreviation. Although trigonometric methods developed in ancient mathematical traditions, the discipline became a distinct field during the Renaissance as European scholars applied the mathematics of triangles to astronomy and practical measurement. Its combination of precise calculation and broad usefulness makes trigonometry a foundational subject for many branches of science and technology.
nounThe branch of mathematics concerned with the relationships between the angles and sides of triangles. It also includes trigonometric functions, such as sine, cosine, and tangent, which describe these relationships and have applications in geometry, physics, engineering, surveying, and astronomy.
- The branch of mathematics concerned with the relationships between the angles and sides of triangles, including the study of trigonometric functions.
"The surveyor used trigonometry to calculate the height of the distant tower from its shadow."
"She used trigonometry to work out the angle of elevation of the aircraft."
"The course introduces students to the trigonometric identities used in physics and engineering."
Trigonometry is normally an uncountable noun and is used in the singular, as in “Trigonometry is used in surveying.”
"The students are studying trigonometry before beginning their physics course."
Trigonometry began as the mathematics of measuring triangles, but its sine, cosine, and tangent functions now help describe everything from the orbit of a planet to the path of a rolling wheel.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does trigonometry come from?
Trigonometry comes from Greek trigonon, meaning “triangle,” and trigonometria, meaning “measurement of triangles.” The word entered English in the early 17th century in connection with the mathematical study of triangles and astronomical calculation. Related forms such as trigonal and trigone preserve the same Greek root, reflecting its continuing association with three-sided figures.
Related word forms
How trigonometry is actually used
Trigonometry is normally used as an uncountable noun. In informal educational contexts, it may be shortened to “trig,” but the full word is preferred in formal writing.
Easily confused with trigonometry
Geometry is the broader branch of mathematics concerned with shapes, space, and properties of figures, whereas trigonometry is the area that focuses specifically on the relationships between angles and sides of triangles.