This is the 4725th most frequent Turkish word.
deki
"In the" or "on the", used to indicate location or possession within or on something.
In this sentence, 'deki' is attached to 'kitap' and used to specify the location ('in the book') of the pictures being described.
Kitaptaki resimler çok güzel.
The pictures in the book are very beautiful.
Here, 'deki' combined with 'üstün', forming 'üstündeki', indicates that the plate is located on the table.
Masanın üstündeki tabak kırılmış.
The plate on the table is broken.
In this example, 'deki' appended to 'bahçe' specifies the flowers' location ('in the garden').