an encyclical issued by Pope Leo XIII on Aug. 4, 1879, which strengthened the position of the philosophical system of the medieval Scholastic philosopher-theologian St. Thomas Aquinas and soon made Thomism the dominant philosophical viewpoint in Roman Catholicism.
AETERNI PATRIS
Meaning of AETERNI PATRIS in English
Britannica English vocabulary. Английский словарь Британика. 2012