The Christian doctrine of the Trinity defines God as three divine ‘persons’ or hypostases: the Father, the Son (Jesus Christ), and the Holy Spirit; “one God in three persons”. The three persons are distinct, yet are one “substance, essence or nature”. According to this doctrine, there is only one God in three persons, yet each person is God, whole and entire.
This of course is a contradiction: there is just one God, Jesus is completely God, yet so are the other two individuals (Father and Holy Spirit) which makes a total of 300% – three gods! Christians describe this incoherence euphemistically as a ‘mystery’.
Mathematicians might use a different word to describe it.
I believe it is polytheism.