Why is the Sargasso Sea called a sea without shores?

The Sargasso Sea is a section of the ocean that cannot be called a sea by all its characteristics, but as we can see, today it is referred to as the sea. This is due to the fact that in the usual sense, the sea should have shores, wash some land, but not the Sargasso Sea. The fact is that the sea located in the Atlantic Ocean is formed as a result of ocean currents.
Form the Sargasso Sea:
The Gulf Stream, which flows in the west, the North Atlantic, which flows in the north, the Canary current, which flows in the east, and the trade wind flowing in the south, limit the area in the Atlantic Ocean, which is called the Sargasso Sea. But why is it called the sea? It is called the sea because the waters of the sea do not mix with the rest of the Atlantic Ocean, as it is limited by ocean currents. Therefore, the Sargasso Sea is called the “sea without shores”.
But why is the sea called Sargasso? The fact is that the sea is covered with numerous floating algae, and when in 1492 Christopher Columbus sailed this sea, his sailors called these algae “sargasso” because they floated and moved with the help of bubbles and resembled a grape variety from Portugal.