Here are all the possible meanings and translations of the word Assyria. Princeton's WordNet(0.00 / 0 votes)Rate this definition: Assyria(noun) an ancient kingdom in northern Mesopotamia which is in present-day Iraq. Assyria. Assyria, was a Semitic Akkadian kingdom, existing as a nation state from the late 25th or early–24th century BC until 605 BC. Assyria was centered on the Upper Tigris river, in northern Mesopotamia. The Assyrians came to rule powerful empires a number of times through history.