Why North Sea and not North Ocean?

The North Sea is called differently from the Northern sea because, geographically, it is its own sea, bounded by Europe in the south, Great Britain in the west, Norway, Denmark, Germany, the Netherlands, and Belgium in the north. It is a marginal sea of the Atlantic Ocean and covers an area of about 570,000 square kilometers. In contrast, the term Northern sea generally refers to the entirety of the marine areas in the northern part of the Northern Hemisphere, which span between various coastal countries. The North Sea, on the other hand, is a clearly defined marine region with its own distinctive character and ecosystem.

The North Sea owes its name largely to its geographical location in northern Europe and its separation from other marine areas by various countries. It is a significant area for fishing, trade, and shipping and plays an important role in the Atlantic Ocean's ecosystem. Its salty water, tides, and diverse Fauna and Flora make the North Sea a unique and fascinating habitat.

Although the term Northern sea might initially seem more appropriate to describe all northern marine areas, the designation North Sea has become established in geography to refer specifically to this particular marine area. Thus, a clear distinction is made between the North Sea as its own sea and the Northern sea as a collective term for all northern marine areas.