Adelphopoiesis
Adelphopoiesis or adelphopoiia (from the Greek ἀδελφοποίησις/ἀδελφοποιία, derived from ἀδελφός, adelphos, lit. 'brother', and ποιέω, poieō, lit. 'I make', literally 'brother-making') is a ceremony practiced historically in Eastern Christian tradition to unite together two people of the same sex (normally men) in a church-recognized relationship analogous to siblinghood. Such ceremonies can be found in the history of the Catholic Church until the 14th century and in the Eastern Orthodox Church until the early 20th century.