An East-Asian parallel to the concept of "ruling prince" would be the term 王 (pronounced wáng in Mandarin, wong4 in Cantonese, ō in Japanese, wang in Korean, and vương in Vietnamese), which commonly refers to Korean and non-East-Asian "kings", but usually means non-imperial monarchs (who would go by 皇帝 ("emperor") instead) in ancient China, and therefore is frequently translated to "prince", especially for those who became rulers well after to the first adoption of the title 皇帝 by Qin Shi Huang.
From the Late Middle Ages, it referred to any vassal of the Holy Roman Emperor ruling over an immediate estate.
The hereditary rulers of the one-time principalities of Bulgaria, Serbia, Montenegro, and Albania were also all referred to in German as Fürsten before they eventually assumed the title of "king" (König).
Fürst is used more generally in German to refer to any ruler, such as a king, a reigning duke, or a prince in the broad sense (compare Niccolò Machiavelli's Il Principe).
Before the 12th century, counts were also included in this group, in accordance with its usage in the Holy Roman Empire, and in some historical or ceremonial contexts, the term Fürst can extend to any lord.
A derivative of the Latin princeps (a Republican title in Roman law, which never formally recognized a monarchic style for the executive head of state but nominally maintained the Consuls as collegial Chief magistrates) is used for a genealogical prince in some languages (e.g., in Dutch and West Frisian, where a ruler is usually called vorst and foarst, respectively), but a prince of the blood is always styled prins.