Today I found myself questioning whether there's a connection between basil the plant and basilica the type of church. Turns out that there is! The word basil comes from French basile, which, through Latin, comes from the Ancient Greek word for "king", basileus. This is because basil was traditionally considered a royal plant, as it was possibly used in some baths or medicines drawn up for kings. Before this, basileus came from Proto-Hellenic gwatileus, which meant something more like "chieftain". This may not be PIE, as it has a hypothesized Pre-Greek origin. Meanwhile, basileus also evolved to give us the Greek word basilike, which meant "royal hall". Eventually, the regal sense evolved into an ecclesiastical one, and by Latin basilica it was the same as the word we know today. There's a third word I suspected of being connected, basilar as in a type of membrane in the ear, but apparently it's uncorrelated. Despite that disappointment, I find it insanely interesting how both a plant and a building are etymologically connected to a dead word for "king".
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