The word cul-de-sac just means "a dead-end road" to us today, but it means "bottom of the sack" in the original French. This will not come as a surprise to many, but the crazy connection we'll make later will be. First, let's get sac out of the way. Also an English word describing biological bags, it comes (the former through Old French sac, with the same meaning, and the the latter through Old English sacc, "cloth bag") from the Latin word saccus, from Ancient Greek sakkos (meaning "bag" still), which may have Semitic or Phoenician origins. De, from Latin de, just expresses belonging. It gets interesting with the first word, cul. It comes from the older French word cul, which meant "backside". This kind of makes sense with the "end" or "bottom" meaning. However, what you weren't expecting is that cul is also the etymon of tutu, the skirt ballerinas wear. Eventually it was modified to cucu, and the cs got switched to ts. The correlation is clear: a tutu is worn over the backside. Anyway, French cul comes from Latin culus, a rude word for "posterior", which can be reconstructed as deriving from the Proto-Indo-European zero-grade kuhl, "to cover".
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