It has sets of 3 leaves. That means it's either trifoliate or a trifoliate hybrid.
You might have bought it as "Japanese Bitter Orange", a relatively common garden ornamental.
Or it's possible the top part orange died and what's left is the trifoliate orange rootstock it was growing on.
It's most likely not going to taste good (unless this happened to be some rare unusual trifoliate hybrid, which is not likely).