This is the 263rd most frequent Indonesian word.
satunya
"The one" or "the only one."
The word 'satunya' here functions as a specific pronoun to refer to one member of a predefined set.
Dia memiliki dua teman, yang satunya sangat pandai matematika.
They have two friends, one of whom is very good at mathematics.
The word 'satunya' emphasizes uniqueness or exclusivity.
Saya hanya ingin membeli buku ini karena ini adalah satunya yang saya butuhkan.
I only want to buy this book because it's the only one I need.
The word 'satunya' in this sentence indicates the only individual with a specific trait within a context.