This is the 32nd most frequent Finnish word.
jonka
"Jonka" means "whose" or "whom" (relative pronoun).
Here, 'jonka' indicates possession in the relative clause, meaning 'whose'.
Tämä on talo, jonka katto on punainen.
This is the house whose roof is red.
In this sentence, 'jonka' is used to link the relative clause to the noun, expressing possession, referring to 'author' as being associated with 'book'.
Löysin kirjan, jonka kirjoittaja on tunnettu.
I found a book whose author is well-known.
In this sentence, 'jonka' introduces a relative clause meaning 'whom', where it serves as the object of the verb 'tapasin'.