This is the 9745th most frequent Turkish word.
arkadaşımızın
"Of our friend"
The word 'arkadaşımızın' is used in the genitive case here, indicating possession ('our friend's').
Arkadaşımızın yardımına ihtiyacımız var.
We need our friend's help.
The word 'arkadaşımızın' again shows possession, referring to something belonging to 'our friend'.
Bu, arkadaşımızın evi.
This is our friend's house.
Here, 'arkadaşımızın' denotes possession, specifying that the mentioned birthday belongs to 'our friend'.