This is the 361st most frequent Czech word.
německu
"Germany" (dative or locative case of "Německo").
In this sentence, 'Německu' is the locative form of the word 'Německo' ('Germany') in Czech, indicating the location where the action took place.
Studoval jsem v Německu několik let.
I studied in Germany for several years.
Here, 'Německu' is in the genitive case, used to express origin or source in Czech.
Má rodina pochází z Německu.
My family comes from Germany.
In this context, 'Německu' is again in the locative case, specifying the place related to the action of learning.