This is the 6086th most frequent Polish word.
amerykanów
The word "amerykanów" is the genitive plural form of "Amerykanin," meaning "of Americans" in English.
Here, "amerykanów" is used in the accusative case, referring to direct interaction with "Americans".
Dzisiaj spotkałem grupę amerykanów w parku.
Today I met a group of Americans in the park.
In this sentence, "amerykanów" is in the genitive case, indicating possession or association.
To jest dom amerykanów, którzy tutaj mieszkają.
This is the house of the Americans who live here.
Here, "amerykanów" functions in the accusative case, used for the direct object of the negated verb "nie widziałem".