* We call it “sine” because when Europeans were translating Arabic works into Latin (because of course they were), the Latin word sinus (meaning “the hanging fold in the upper part of a toga”) was the closest match they could find for the Arabic word used, which was jaib, meaning “pocket, fold, or purse.” But the word “jaib” wasn’t even being used! It was jyb, which was the way the Arabs had come up with to write the Sanskrit word they were translating, jyā, into their alphabet. That word has its origins in the ancient Greek word for “string.” Anyway! Feel free to name this function anything else, because you can hardly end up with a more arbitrary word than we did.