- 1三角函數／三角學（學校裡常說「三角」）。注意台灣高中課本多寫「三角函數」，不是「三角形」（那是 triangle）。
The part of maths that studies triangles — specifically, how the angles of a triangle and the lengths of its sides are tied to each other. If you know some of them, trigonometry lets you work out the rest. That is why it is not just school homework: it is how people measure a mountain they cannot climb, how a ship finds its position, how a phone works out where you are, and how computers draw anything that moves. Its famous words are sine, and tangent, usually written sin, cos, tan.
It is an uncountable noun, so no 'a' and no plural: you study trigonometry, you have a trigonometry test. In everyday speech almost nobody says the whole word — students say trig, which rhymes with 'big'. The adjective is trigonometric (a trigonometric function). Say it try-guh-NOM-uh-tree: five beats, with the stress on NOM.
組成希臘文 τρίγωνον trigonon「三角形」（tri- 三 + gonia 角）+ metron「測量」→「三角形的測量」。1610 年代經新拉丁文 trigonometria 進入英文。
同家族的字
- polygonshares Greek gonia 'angle' — a shape with many angles
- pentagonshares Greek gonia 'angle' — five angles
- geometryshares Greek metron 'measure' — measuring the earth
- thermometershares Greek metron 'measure' — measuring heat
- tricycleshares tri- 'three'
原始詞典資料1 筆記錄
以下是外部詞典記錄的用法，摘錄並精簡格式，我們還沒有寫成教學內容。上面的說明才是我們自己寫的；有些用法可能上面已經講過了。
trigonometrynoun/ˌtɹɪɡəˈnɒmətɹi/
- 1
geometrymathematical-analysismathematicsThe branch of mathematics that deals with the relationships between the sides and angles of (in particular) right-angled triangles, as represented by the trigonometric functions, and with calculations based on said relationships.
- Trigonometry emerged in the Hellenistic world during the 3rd century BCE from applications of geometry to astronomy; the Greeks focused on the calculation of chords, while mathematicians in India created the earliest known tables of values for trigonometric functions such as sine.
- Historically, trigonometry has been applied in areas such as geodesy, surveying, celestial mechanics and navigation.
摘錄自 英文維基詞典 English Wiktionary，已精簡格式；依 CC BY-SA 4.0 授權使用，改動後的內容同樣以此授權提供。