Text: The Origin of the Word Sine submitted by Kirby Smith, TAMU Did you ever wonder about the origin of the word sine in trigonometry? Joseph Rotman offers a possible explanation in his new book Journey into Mathematics published by Prentice Hall. I quote from the author: "The fifth century Indian mathematician Aryabhata called the sine ardha-jya (half chord) in Sanskrit; this term was later abbreviated to jya. A few centuries later, books in Arabic transliterated jya as jiba. In Arabic script, there are letters and diacritical marks; roughly speaking, the letters correspond to our consonants, while the diacritical marks correspond to our vowels. It is customary to suppress diacritical marks in writing; for example, the Arabic version of jiba is written jb (using Arabic characters, of course). Now jiba, having no other meaning in Arabic, eventually evolved into jaib, which is an Arabic word, meaning 'bosom of a dress' (a fine word, but having nothing to do with half-chord). Finally, Gherardo of Cremona, ca. 1150, translated jaib into its Latin equivalent sinus (this Latin word has many meanings, all related to curved shapes). And this is why sine is so called, for sine means bosom!"

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