This is the 189th most frequent Turkish word.
bunun
"Of this" or "this one's."
'Bunun' is used to refer back to an already mentioned subject, showing possession and specificity.
Bu kitabın içindeki resimler gerçekten güzel, ama bunun kalitesi düşük.
The pictures inside this book are really nice, but the quality of this one is low.
Here, 'bunun' is a demonstrative pronoun used to refer to something specific being discussed, translating as 'of this'.
Bunun ne anlama geldiğini biliyor musun?
Do you know what this means?
In this sentence, 'bunun' points back to the painting mentioned earlier and specifies 'its' color.