This is the 2319th most frequent German word.
kassel
"Kassel" is a city in central Germany.
Here, 'Kassel' is a proper noun referring to the geographical entity of Kassel, a city in Germany.
Kassel ist eine Stadt in Hessen.
Kassel is a city in Hesse.
In this sentence, 'Kassel' functions as the destination of the action of traveling, indicating it as a place.
Ich werde morgen nach Kassel reisen.
I will travel to Kassel tomorrow.
Here, 'Kassel' is used to indicate the location where the Brothers Grimm resided, again referring to it as a place.