There are two opinions in this matter. Common thing in them is that they do not consider it part of eyebrows. Where they differ is that if a woman is allowed to pluck any hair from her face, some consider only eyebrows etc which are prohibited to pluck. While other consider all facial hair in the ruling of not allowed to pluck.
Now, if you satisfy your-self with either of these views on plucking facial hair from face, you should follow that ruling. To me, i think it is permitted to pluck other hair than eyebrows etc form face for women, if needed(should avoid unnecessarily and should not make it habit).
PS: I know this partially answers your question, but i am deliberately not jumping in the discussion of if plucking hair from whole face is prohibited or not. Because it will be better in another question, with matching title, and will also be easy for people to find in future. I encourage you to post a new question about that if you need clarification, and provide that question's link in comment.