The Armenian Apostolic Church adheres to Miaphysitism, a Christological doctrine that affirms Jesus Christ is one person with one nature (mia physis), where His full humanity and full divinity are united without separation, confusion, or alteration, following the teachings of St. Cyril of Alexandria. This position rejects both Eutychian Monophysitism (only one divine nature) and the Chalcedonian Dyophysitism (two separate natures in one person) of Eastern Orthodoxy and Catholicism, defining its unique path as Oriental Orthodoxy after rejecting the Council of Chalcedon in 451 AD. 

Key Aspects of Armenian Miaphysitism:

• One United Nature: Christ's humanity and divinity are inseparable and form a single, unified nature, not two distinct ones.

• Rejection of Monophysitism: Armenians reject the idea that Christ only had a divine nature, emphasizing His full humanity.

• Rejection of Chalcedon: They also reject the Council of Chalcedon (451 AD) which defined Christ as one person in two natures (Dyophysitism), seeing it as a deviation from Cyril's teachings.

• Cyriline Foundation: Their doctrine is rooted in the Christology of St. Cyril of Alexandria, who spoke of "one incarnate nature of God the Word" (mia physis tou Theou Logou). 

Historical Context:

• The Armenian Church broke communion with Rome and Constantinople following the Council of Chalcedon, formally solidifying its Miaphysite stance at the Third Council of Dvin in 506 AD.

• This position places the Armenian Church within the Oriental Orthodox Communion, alongside Coptic, Ethiopian, Syriac, and Eritrean Churches, all adhering to Miaphysitism. 

In essence, Miaphysitism for the Armenian Church means Christ is truly God and truly Man, existing in one inseparable divine-human nature, a distinct theological position from both East and West.