This is the 326th most frequent Czech word.
the
The Czech language does not have a direct equivalent for the English definite article "the."
In this sentence, the word 'the' is used to specify a singular, definite object ('the piano') that is already known in the conversation or context.
The klavír ukládali do muzea.
They were putting the piano in the museum.
Here, 'the' marks 'book' as a definite entity, known because of the following descriptor that the book being referred to was recommended.
Přečetl jsem the knihu, kterou mi doporučili.
I read the book that they recommended to me.
In this case, 'the' specifies 'house,' indicating it is unique within its spatial descriptor and known to the listener.