Usage of the genitive case
The main usage of the genitive case is to link nouns or noun phrases wher English would normally use "of". It often indicates possession or ownership:
Grammar 5: The genitive case indicating possession
die Wohnung des Arztes
("the (male) doctor's flat")
die Wohnung der Ärztin
("the (female) doctor's flat")
der Keller des Hauses
("the cellar of the house")
das Zimmer der Kinder
("the children's room")
The genitive can also be used in German to link nouns or noun phrases wher English would normally use "of":
Grammar 6: The genitive case meaning "of"
die Abfahrt des Zuges
("the departure of the train")
die Farbe des Fernsehers
("the colour of the TV set")
die Sanierung des Hauses
("the renovation of the house")
ein Strahl der Hoffnung
("a ray of hope")