Atop has 3 different meanings across 2 categories:
Adverb · Prep
on, to, or at the top
"The eagle perched atop the highest branch of the ancient oak tree."
On, to, or at the top.
"She balanced her hat perfectly atop her head while running through the rain."
On the top of.
"The eagle perched atop the highest branch, surveying the valley below."