Sine

How to spell sine

4 letters · 1 syllable

How to pronounce sine

What does sine mean?

1. nounIn trigonometry, the ratio of the side opposite an angle to the hypotenuse in a right-angled triangle.

Sine in a sentence

• The sine of a thirty-degree angle equals exactly one half.

• To find the missing side, multiply the hypotenuse by the sine of the angle.

Where does sine come from?

Language of origin: Latin

The mathematical sine has one of the most curious histories of any technical term. It begins in Sanskrit, where Indian astronomers used the word jya, meaning 'bowstring', to describe the half-chord of a circle. Arabic scholars borrowed the term as jiba, which was later written in the consonant-only Arabic script in a way that looked identical to jayb, an ordinary word meaning 'bay, pocket, or fold'. When the twelfth-century translator Gerard of Cremona rendered the Arabic into Latin, he chose the Latin sinus, which also means 'a fold, bay, or curve', and that translation stuck. So the modern spelling is a fossil of a centuries-old misreading, and its silent final e marks it apart in writing from its sound-alikes 'sign' and 'sin', even though all three are pronounced the same.

How the word is built

• sine (from Latin sinus: a curve, fold, or bay)

Words that sound like sine

They sound the same but mean different things, so the meaning decides which spelling to write.

• sign: A board, notice, or symbol that conveys information or instruction.