I am looking for the term describing when your hair grows kind of in a circular direction (defined by the direction of your hair root).
Many people have something like this on the back of their heads or even on their foreheads.
I found the term hair crown on dict.cc but I feel like this is either not the correct term for it or it is not very widely used. There is a German article on human hair including a section about these things but I could not find the English equivalent.
In German, these are called Haarwirbel meaning something like hair whirl.
You probably want to use hair whorl. You'll notice that it's virtually the same as the German term, except with the alternate spelling of whorl/whirl. In English, whirl is the verb form, whorl is the noun.