The North Sea is the part of the Atlantic Ocean situated between the west coast of Norway and the east coast of Britain. There is a substantial amount of oil and natural gas under the seabed: see North Sea oil. A bay of the North Sea is Kattegat, between Denmark, Norway, and Sweden, which connects to the Baltic Sea through Íresund, Great Belt and Small Belt. In the south, the North Sea connects with the rest of the Atlantic through the English Channel and in the north through the Norwegian Sea.
Major waterways that drain into the North Sea include the Kattegat (which drains the Baltic Sea), the Elbe (at Cuxhaven), the Weser (at Bremerhaven), the Ems at Emden, the Rhine and Meuse (at Rotterdam), the Scheldt (at Flushing), the Thames, and the Humber (at Hull).
In classical times this body of water was referred to as the Oceanum- or Mare Germanicum, meaning German Ocean or Sea. This name was commonly used in English and other languages until the early eighteenth century, but by the late-nineteenth century it was a rare, scholarly usage even in Germany. Its modern name is thought to have originated from a Frisian point of view which lies directly to the south of the North Sea (also see Zuiderzee).