At first blush, the word bonfire might appear to be from the French word for "good", bon, plus the word fire. Indeed, many early dictionaries, including Samuel Johnson's Dictionary of the English Language and Webster's Dictionary, claimed that, but this violates spelling change rules and doesn't make historical sense, and the reference books were corrected around the turn of the twentieth century. The first element of the word actually comes from the English word bone, because it used to be a practice to burn bones (apparently you can do that) in honor of certain saints. Later on, the original meaning was entirely forgotten and the e was dropped from the word because of analogy with the French adjective.
Hello! I'm Adam Aleksic. This year, I graduated from Harvard University with a degree in Government and Linguistics. There, I co-founded the Harvard Undergraduate Linguistics Society and wrote a thesis on Serbo-Croatian language policy, magna cum laude. In addition to etymology, I also really enjoy philosophy, trivia, vexillology, geography, board games, conlanging, art history, and law.