This is the 995th most frequent Turkish word.
in
The Turkish word "in" means "den" or "cave."
Here, "in" is used as a possessive suffix, indicating that the garden belongs to the house.
Evin bahçesi çok geniş.
The house's garden is very spacious.
In this sentence, "in" is part of "içindeki," enhancing the meaning to denote something being inside and belonging to the book.
Kitabın içindeki resimler çok güzeldi.
The pictures inside the book were very beautiful.
In this context, "in" is part of the word "ince," which means thin, and does not function as a suffix.