This is the 1428th most frequent German word.
kursk
"Kursk" is not a German word; it is the name of a city in Russia.
In this sentence, 'Kursk' is used as a proper noun to refer to the name of a specific submarine.
Der Kursk war ein U-Boot der russischen Marine.
The Kursk was a submarine of the Russian navy.
Here, 'Kursk' refers to the submarine in the context of the events that transpired involving it. The word is used symbolically to represent the historical incident.
Die Geschichte des Untergangs von Kursk ist tragisch.
The story of the sinking of Kursk is tragic.
In this instance, 'Kursk' is again used as a proper noun for the submarine, with the focus being on its historical and potentially educational relevance.