On the 12th of May in the year 1588, during the French Wars of Religion, an uprising in Paris called the Day of the Barricades temporarily ousted King Henry III from Paris. In it, the townspeople blocked off major entryways and points in the city and generally rioted until the Bastille surrendered. This was the first time barricades were set up in a Parisian revolt, but far from the last, as that would become a tactic used many times over. In this first barricade, it had to be set up quickly, so the rioters used anything on hand, including barrels full of soil and stones. The barrels were used so much that they took the Spanish word barricada, which literally meant "made of barrels", from the root barrica, "barrel". In older times, this was spelled barril, and before that, it likely came from Latin, because there are cognates in basically all of the Romance languages. However, there are no records of such a word, so this is just conjecture. It makes so much sense in retrospect; I can't believe the etymology was under my nose the whole time and I never noticed.
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.