It occurred to me that Europeans got cotton from the Arabs, so shouldn't the word be Arabic too? Turns out I was right! In Middle English, cotton was couton, and that came from the Anglo-Norman word coton. The word that passed through either French, Italian, or Spanish (there is no agreement among linguists there) to come back to the Arabic word qutn, still with the current definition. Through local dialects, qutn can be traced to the Egyptian root qtn (no vowels in Ancient Egyptian, remember), still meaning "cotton". The lack of semantic change is obvious; the word always described that crop, which has been around almost as long as language has. Etymologists struggle going further, but it is theorized that it can be traced to an Akkadian word that meant "flax" or "linen". If true, this descended from East Semitic and is ultimately from Afro-Asiatic.
Adam Aleksic has been described as the internet's sixth most famous etymologist. He loves writing about himself in the third person, he's a freshman at Harvard University, and he has disturbing interests in linguistics, vexillology, geography, board games, limericks, and law.
The Etymology Nerd