(Christianity) any of about 70 theologians in the period from the 2nd to the 7th century whose writing established and confirmed official church doctrine; in the Roman Catholic Church some were later declared saints and became Doctor of the Church; the best known Latin Church Fathers are Ambrose, Augustine, Gregory the Great, and Jerome; those who wrote in Greek include Athanasius, Basil, Gregory Nazianzen, and John Chrysostom

(Roman Catholic Church) a title conferred on 33 saints who distinguished themselves through the orthodoxy of their theological teaching

a person who has died and has been declared a saint by canonization

someone who is learned in theology or who speculates about theology