Ancient Indians in the Gupta Empire invented the sine and other trigonometric functions. They called this the jaya, which meant "chord". Once the Gupta declined and the Muslims emerged as the leading intellectuals of the world, they borrowed the sine, and with it, the Sanskrit word for "sine". However, they only kept the phoneme, which was phonetically transcribed to jiba. This meant that the word had no real meaning, but was assigned to the sine function nonetheless. Later still, when Europeans wanted to borrow the word, they messed things up and confused jiba with jaib, the Arabic word for "bosom". So, while intending to borrow a term for a mathematical function, they mistranslated it, and ended up using sinus, which was the Latin word for "bosom". This easily became "sine" when it was borrowed into English in the 1590s. Sinus, which has nothing to do with the nose, is of unknown Proto-Indo-European origin. The co- in cosine was correctly translated from kotiya as meaning "complementary", so a cosine is a "complementary sine" or "complementary bosom".
Another term for groundhog is woodchuck, but the -chuck part used to refer to a different animal: the marten, or fisher, is a carnivorous mustelid that sort of shares a resemblance to the woodchuck, an animal associated with wood. So, where does chuck come from? Algonquian Native American languages. It is theorized that it either comes from the Cree word otchek or the Ojibwa word otchig, both still meaning "martin". The wood- part of woodchuck is pretty obvious and boring, but here goes: through Old English widu, meaning "forest", this comes from the Proto-Germanic word widu, which comes from the Proto-Indo-European root widhu, still with the same definition. Also, let me spoil things for you and tell you that chuck, meaning "throw", comes from French choquer, meaning "to strike", and the word could comes from a Proto-Indo-European root sounding like gno and meaning "to know", so the question how much wood could a woodchuck chuck if a woodchuck could chuck wood can be rewritten as how much widhu gno a widhuotcheck choquer if a widhuotcheck gno choquer widhu and translated to "how much forest know a forest marten strike if a forest marten know strike forest". Language is so malleable! Happy Groundhog Day!
Somebody asked me today where the word shindig comes from, and the answer is quite engrossing. Meaning "a lively party", this term emerged in the 1870s with mysterious origins. It's possible that it comes from the Scottish word shinty, describing a game similar to hockey, which has a commotion similar to parties. Alternatively, it could be from Gaelic sinteag, meaning "to leap", from Irish shindy, meaning "a spree", or even shinny, another word for hockey. All of these possible origins have one thing in common: they are not Germanic. Rather, they derive from Celtic, which is one of the reasons for their collective obscurity- it is a poorly documented and reconstructed language. Interestingly, usage of the word "shin-dig" is higher than ever; you would think, as an old-timey term, it would have been most used in prior years; however, there's been a recent boom in frequency of shindig. Whether a leap, a spree, or hockey, this word is weird.
Hello! I'm Adam Aleksic, a sophomore studying government and linguistics at Harvard University, where I co-founded the Harvard Undergraduate Linguistics Society. In addition to etymology, I also really enjoy politics, vexillology, geography, board games, conlanging, and law.