We've seen that Lucifer means light-bringer, but now somebody requested the word Satan. While researching, I found the etymology to be fairly straightforward, but there were some interesting side Easter eggs! For example, did you know that Satan is actually a genus name for an ugly kind of fish? And that Lucifer should not be used interchangeably with Satan, for the former refers only to the angel before he fell, and vice versa for the latter? Anyway, onto the origin. Satan, through languages the Bible's been reprinted in, can be traced to Old English, Latin, and farthest back, Greek. This Greek Satan is from the Hebrew word satan (no capitalization) which just meant "adversary", a definition which makes sense. Due to a cognate in the other Semitic language of Arabic, linguists reconstruct this as from a root stn, again with the same meaning, and probably from Proto-Afroasiatic through Proto-Semitic. Really old words like this are hard to etymologize.
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.