How "Sine" Came from Bosom

The mathematical function sine has its name thanks to a centuries-old mistranslation. The concept originated in India, where it was called jya-ardha ("half-chord"), later shortened to jiva. When translated into Arabic, the phrase became "jiba," but because Arabic script often omitted vowels, later translators confused it with "jaib," meaning "bosom" or "fold." From there, Latin scholars rendered it as sinus (also meaning "bosom"), which eventually gave us the English word "sine." What began as a simple geometric term ended up with a completely unrelated anatomical name due to linguistic mix-ups.

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