The Great Deputy King, in full Maha Uparaja Anaukrapa Ainshe Min, incorrectly interpreted as Crown Prince by Europeans, and addressed as His Royal Highness, was the single highest rank among the Min-nyi Min-tha, i.e. princes of the royal blood. It is shortened to Ainshe Min (အိမ်ရှေ့မင်း, IPA: [èiɰ̃ʃḛ mɪ́ɰ̃]).
However, the position was not reserved for the highest birth rank (if there is one, Shwe Kodaw-gyi Awratha, i.e. eldest son of the sovereign, by his chief Queen), nor did it carry a plausible promise of succession, which was usually only settled in an ultimate power struggle.
The word Ouparach (Khmer: ឧបរាជ) is derived from both Sanskrit and Pali languages, literally means Vice King, who obtains the position following the crowned king. The full term of Ouparach in order to provide the proper honor is Samdach Preah Ouparach (Khmer: សម្តេចព្រះឧបរាជ) or Samdach Preah Moha Ouparach (Khmer: សម្តេចព្រះមហាឧបរាជ្យ). According to tradition of Kingdom of Cambodia, Samdach Preah Moha Ouparach positions as the supreme official controlling other high and low officials.[2]
Khmer dictionary, adapted from Samdach Chuon Nat Khmer dictionary, page 1643, published in 2007.