Die schwache Deklination (oder n-Deklination).
Anybody having learnt Latin knows that there are several declinations. Here I would like to pinpoint to the weak declination of nouns in German. Weak nouns are mainly used for male persons (something for the ladies to laugh at). A typical example: Der Junge. In the accusative/dative: den Jungen/dem Jungen. All plural cases are also 'Jungen'.
Some other nouns are weak e.g.
- der Name, der Zeuge,
- der Kommilitone (another one from the DL course)
There is only one neutral weak noun: das Herz.
Ich trage dich im Herzen. Freely: You're in my heart.
You find more on : https://mein-deutschbuch.de/n-deklination.html