quaternity
/kwəˈtəːnɪti/noun
1A group or set of four persons or things; especially a group of four persons or aspects seen as comprising the Christian Godhead (in contrast to the three of the Trinity).
2The fact or condition of being four in number, or an aggregate of four.
Origin
Early 16th century; earliest use found in Thomas More (1478–1535), lord chancellor, humanist, and martyr. From Middle French quaternité set of four, dogma stating that four persons comprise the Christian Godhead and its etymon post-classical Latin quaternitas group of four aspects of the Christian Godhead from classical Latin quaternī set of four + -tās, after post-classical Latin trinitas.