What it is: Probably Megiddo, the site of a mountain fortress in what is now northern Israel. According to the Old Testament of the Bible, a number of fierce battles took place there. It was also a scene of conflict in 1918, during the First World War.
What it means: Armageddon is named in Revelation, the last book of the Christian New Testament, as the future site of the last battle between good and evil, marking the end of the world as we know it. The prophecy is regarded symbolically by mainstream Christianity, but is taken seriously by some fundamentalist sects which take every word of the Bible as literallly true. The word Armageddon is now used generally to refer to any particularly destructive conflict, such as the First World War - which for a time people did think was the 'war to end all wars'.
Think about it: Whatever your religious belief, or if you have none, the name of Armageddon can still evoke in some people a shiver of apprehension, even horror. Other names of real places can have resonance, too, good or bad. They usually refer to a significant part of a history, of an individual or group or nation, and just the name can stand for a whole event. Sadly, they are often the sites of past battles. (Troy, Waterloo, Ypres.) Is this the kind of power a place-name ought to have? Does it sustain the misleading link between fighting and heroism? Can it mask the realities of what actually happened?