What is the origin of sine, cosine, tangent, secant, cosecant, cotangent?
Sine The name sine came to us from the Latin sinus, a term related to a curve, fold, or hollow. It is often interpreted as the fold of a garment, which was used as we would use a pocket today. The use in mathematics probably comes about through the incorrect translation of a Sanskrit word. Here is a brief description of how that came about from Passage to China by Amartya Sen. “In his Sanksrit mathematical treatise completed in 499 AD, Aryabhata used jya-ardha (Sankscrit for “chord half”), shortened later into jya, for what we now call “sine.” Arab mathematicians in the eighth century transliterated the Sanskrit word jya into the proximate sound of jiba and then later changed it into jaib (with the same consonants as jiba), which is a good Arabic word, meaning a bay or a cove, and it was this word that was later translated by Gherardo of Cremona (circa 1150) into its equivalent Latin word for a bay or a cove, viz., sinus, from which the modern term “sine” is derived.” COSINE was origin
