The etymology of kitten is unbelievable! Its first appearance is in Latin, where it originally took the form catulus, meaning "dog". The Romans then began to associate four-legged creatures a little differently, and gave kitten/cat its own word, cattus. At this point, the etymologies of cat, "older domestic feline", and kitten, "younger domestic feline", split for millennia. Kitten traveled through thousands of years of French as chatoun, then chitoun, then kittoun in England, and finally kitten today. Cat, meanwhile, took the Germanic route, diffusing into Proto-Germanic as kattuz (from cattus, remember, not such a shocking change) and then somehow changing into the English language as catt around 700 CE. This later became cat, which was a simple matter of dropping a letter. Ergo, dog is nearly as strong of a relative of cat as kitten is, and the latter two have been developing independently for thousands of years until their reunion in the English language. This is why etymology is so awesome!
Adam Aleksic, a freshman studying linguistics at Harvard University, has been described as the internet's sixth most famous etymologist. He has disturbing interests in words, vexillology, geography, board games, limericks, and law, and he loves writing about himself in the third person.
The Etymology Nerd