We've had the word cadence in some form since the late fourteenth century. It was taken from Middle French, eventually deriving from the Old Italian noun cadenza, which meant "end of a musical movement". More literally, it was "a falling", because that, through Vulgar Latin cadentia, comes from the verb cadere, which means "to fall" (the connection was that many songs are concluded with a falling tone, and then that was extended to the flow of rhythm in general). By way of Proto-Italic kado, cadere (which additionally gave us the words case, cascade, cadaver, coincidence, chute, and accident) eventually derives from the Proto-Indo-European reconstruction kad, also "fall". The word cadence has remained relatively constant in usage throughout the years, constituting about 0.00015% of all written English.
Adam Aleksic, a rising sophomore studying linguistics and government at Harvard University, has been described as the internet's sixth most famous etymologist. He also has disturbing interests in politics, vexillology, geography, board games, conlanging, and law.