Final answer:
The area between the Bosporus and the Hellespont is known as the Sea of Marmara. It is a significant maritime route connecting the Black Sea to the Aegean Sea, and it lies between the European and Asian parts of Turkey.
Step-by-step explanation:
The small water area between the Bosporus and the Hellespont does not have a specific name as it is a part of the larger body of water surrounding the area, but the description closely matches the Sea of Marmara. The Sea of Marmara is an inland sea that connects the Black Sea to the Aegean Sea via the Bosporus and the Dardanelles (or Hellespont). It serves as a vital waterway for Istanbul and the surrounding regions, positioned between the European and Asian parts of Turkey. Moreover, the Sea of Marmara, combined with the Bosporus and the Dardanelles, comprises an important maritime route, historically significant for trade and military as it connects various significant bodies of water and surrounding regions.