This is the 6998th most frequent Polish word.
grzybowskiej
"Grzybowskiej" is the genitive or locative form of "Grzybowska," typically referring to something or someone associated with Grzybowski (e.g., Grzybowska Street or a surname).
Here, 'Grzybowskiej' is a locative case referring to being at a specific location, i.e., Grzybowska Street.
Spotkaliśmy się na ulicy Grzybowskiej.
We met on Grzybowska Street.
In this context, 'Grzybowskiej' denotes possession in the genitive case, referring to something belonging to a person named Grzybowska.
To należy do pani Grzybowskiej.
This belongs to Mrs. Grzybowska.
Here, 'Grzybowskiej' showcases the instrumental case, indicating the person with whom the conversation took place.