This is the 510th most frequent Slovak word.
ktorými
"Which" or "by which" (instrumental plural form).
The word 'ktorými' in this sentence is used as a relative pronoun to refer back to 'books' in an instrumental case, showing the means by which the inspiration came.
Sú to knihy, ktorými som sa inšpirovala.
These are the books by which I was inspired.
Here, 'ktorými' serves as a relative pronoun in the instrumental case, referring to 'people' and indicating companionship relating to the action 'talked'.
Videla som ľudí, s ktorými sme hovorili na oslave.
I saw people with whom we talked at the party.
In this example, 'ktorými' is again a relative pronoun, referring to 'roads' in an instrumental sense, combined with the preposition 'po' to describe the manner of movement.