Eorzea is an "idea". It refers to the cultural region that, as observed by others here, comprises most parts of the continent of Aldenard and its outlying islands.

It's like how Europe is also an "idea", one that refers to a particular corner of the Eurasian landmass.

The borders of "Europe" have never been properly defined. The name itself came from a figure in Greek mythology, a Phoenician princess who later became the mother of King Minos of Crete. And, in the earliest days, "Europe" used to refer to just a tiny corner of the Balkans.

Long after the Romans conquered all the lands west of the Rhine, "Europe" came to define the Christian half of the western empire. Yet, despite their shared Christian identity, the peoples of "Europe" never remained united for long. Through the centuries, they were divided along ethnic, language and religious lines.

But despite all these divisions, the idea of a united "Europe" has always persisted. Today, it finds expression through the European Union project. In that endeavour, "Europe" has become something more than a historical memory of a long-gone Christian empire: It's supposed to be a bulwark of western democracies united against countries outside Europe that supposedly aren't as democratic?

Now, if you'd replace the instances of "Europe" in this spiel with Eorzea, the Roman Empire with the Allagan Empire, and Christianity with the worship of The Twelve.

Would that help give you a better grasp of the concept of "Eorzea"?

No? Well, don't worry. Real-life Europeans, in modern times and antiquity, can't quite seem to agree, even today, what "Europe" actually is, either.