Final answer:
Trinitarianism is the theological concept associated with the triune nature of God, representing the Father, Son, and Holy Spirit as coequal parts of one God, central to mainstream Christian doctrine.
Step-by-step explanation:
The theological concept associated with the idea of a triune God and basic perfections about God and biblical theistic beliefs is Trinitarianism. This concept reflects the understanding that God exists simultaneously as three persons: God the Father, God the Son (Jesus Christ), and God the Holy Spirit.
The concept of the Holy Trinity became a defining element of orthodoxy, setting the stage for significant theological disputes and the denunciation of alternative views, such as Arianism, as heresies. Arianism argued against the divine equality of Jesus with God the Father, whereas Trinitarianism affirmed it. Trinitarianism is thus integral to mainstream Christian doctrine, where God is understood to be a unity of three equally divine persons.