This is the 13657th most frequent Russian word.
некоторой
"Некоторой" means "some" or "certain" in English.
In this sentence, "некоторой" is used to describe an approximate or undefined height, giving the idea of specificity without actually defining it.
Я видел книгу на некоторой высоте.
I saw the book at a certain height.
Here, "некоторой" expresses the idea of a particular or specific quality without exact definition, similar to "certain" in English.
Некоторой синонимой может быть "определенной".
A synonym for "некоторой" might be "certain".
In this example, "некоторой" points to an unspecified group, introducing indefiniteness while still characterizing the group as particular.