This is the 13677th most frequent Turkish word.
kuyuda
"In the well."
Here, 'kuyuda' indicates the location where the fountain was found, meaning 'in the well'.
Kuyuda bir pınar buldum.
I found a fountain in the well.
In this sentence, 'kuyuda' describes where the sky was reflected, emphasizing a descriptive usage.
Kuyuda yansıyan gökyüzü beni büyüledi.
The sky reflected in the well mesmerized me.
'Kuyuda' here refers to the place where the action of descending occurs, specifically 'in the well'.