Why was Mesopotamia called the land between the rivers?

The name Mesopotamia is derived from a Greek word meaning "land between the rivers". This designation refers specifically to the region situated between the Tigris and Euphrates rivers.123

These two rivers follow roughly parallel courses through southwestern Asia, originating in eastern Turkey and flowing southeast through Syria and Iraq before emptying into the Persian Gulf. Historically, the fertile soil provided by the annual flooding of these rivers enabled the development of one of the world's earliest cradles of civilization, fostering early agriculture, urbanism, and complex societies.14