Bosnia (Bosna / Босна) – official name Bosna i Hercegovina – is the northern region of Bosnia and Herzegovina, encompassing roughly 81% of the country; the other region, the southern part, is Herzegovina. The two regions have formed a geopolitical entity since medieval times, and the name “Bosnia” commonly occurs in historical and geopolitical senses as generally referring to both regions (Bosnia and Herzegovina). The official use of the combined name started only in the late period of Ottoman-rule.