This is the 1313th most frequent Polish word.
muzeum
A building where objects of historical, artistic, or scientific interest are exhibited.
Here, 'muzeum' refers to a specific type of museum—the historical museum. It is used as the object of the verb 'odwiedziłem' (I visited).
Odwiedziłem wczoraj muzeum historyczne.
I visited the history museum yesterday.
In this sentence, 'muzeum' is the subject of the sentence and is described as being fascinating.
To muzeum jest pełne fascynujących eksponatów.
This museum is full of fascinating exhibits.
Here, 'muzeum' is part of a prepositional phrase 'do muzeum sztuki' indicating a destination.