This is the 760th most frequent Polish word.
niemcy
"Germany" (the country).
In this sentence, 'Niemcy' refers to the country, Germany, as a proper noun.
Niemcy są dużym krajem w Europie.
Germany is a large country in Europe.
Here, 'z Niemiec' indicates the prepositional form to denote origin from Germany.
Mój przyjaciel pochodzi z Niemiec.
My friend comes from Germany.
In this sentence, 'Niemcy' refers to the people of Germany, the Germans, as a plural noun.