"Although the names Syria and Assyria have different origins, authors often treat them as one and the same, and understand them to encompass the same regions.
The name Syrians, which was originally a designation for the Phoenicians, derived from Tyre, their principal city, subsequently became common to the neighbouring peoples as well. The Hebrews called Tyre Tzor or Sur, from which come Surim or Sorim, which are equivalent to Syrians. According to Bochart, the form Syri was derived by adding a prefixed article.
The Assyrians, however, were entirely different from these peoples. Their name derived from Asshur. The Hebrew name for the Assyrians was Ashurim. They lived beyond the Euphrates and Tigris and were initially called Assures. Their name was once common to all those under Assyrian rule. Consequently, many ancient writers used the names Syrians and Assyrians interchangeably, as can be seen in Justin, Book 1, Strabo, Books 2 and 16, and other authors, as the learned scholar points out.
Eventually, however, usage became established whereby the empire was divided into Syrians and Assyrians. The name Assyrians was assigned to those who lived beyond the Euphrates, while Syrians designated the remaining peoples, from Phoenicia to the Euphrates. Thus Hesychius calls Syria the land extending from Phoenicia as far as Babylon.
Before the division of the empire into Assyrians and Syrians, the Syrians were called Arameans, after Aram, the son of Shem. Josephus says this, and Strabo, in Book 16, likewise states that the Greeks called the Syrians Arameans. The Syrians also call themselves Arameans today."