Glossary

Plain-English explanations of 44 words and names you will meet when reading the Fathers. On book pages, the first use of a term is underlined with dots; hover or tap it for a short definition.

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Abba: An Aramaic word for “father”, used as a title of respect for an experienced monk, especially among the Desert Fathers. The female form is Amma.
Anchorite: A Christian who withdraws from society to live alone in prayer, as many early desert monks did. Compare coenobitic.
ANF (Ante-Nicene Fathers): A ten-volume English translation of early Christian writings before the Council of Nicaea (325), edited by Alexander Roberts and James Donaldson (1867–1873; American edition 1885–1896). Several texts on this site come from it.
Ante-Nicene: Belonging to the period before the Council of Nicaea in 325.
Apologist: An early Christian writer who defended the faith in writing to outsiders, such as Roman rulers or philosophers. St Justin Martyr is a well-known example. The word comes from the Greek apologia, “defence”.
Apostolic Fathers: The earliest Christian writers after the New Testament, traditionally thought to have known the apostles or their disciples. They include St Clement of Rome, St Ignatius of Antioch and the author of the Didache.
Arianism: The teaching of Arius, a priest of Alexandria (died 336), that the Son of God was created and is not fully equal to the Father. It was rejected at the Council of Nicaea in 325.
Asceticism: Spiritual discipline such as fasting, vigils, simple living and self-denial, practised to grow in prayer and virtue. From the Greek askesis, “exercise” or “training”.
Cappadocian Fathers: St Basil the Great, his brother St Gregory of Nyssa and their friend St Gregory of Nazianzus, fourth-century bishops from Cappadocia (in modern Turkey) who shaped the doctrine of the Trinity.
Catechumen: Someone receiving instruction in the Christian faith in preparation for baptism.
Chalcedon, Council of: The church council held in 451 that taught that Christ is one person in two natures, divine and human.
Church Fathers: Influential teachers and writers of the early Church, roughly from the first to the eighth century, whose works shaped Christian belief and worship. Their study is called patristics.
Church of the East: The ancient Christian church of the Persian Empire and beyond, which used Syriac. St Isaac the Syrian belonged to it.
Coenobitic: Describing monks who live together in a community under a common rule, rather than alone. From the Greek for “common life”.
Desert Fathers: Christian monks and hermits of the Egyptian, Palestinian and Syrian deserts, especially from the third to fifth centuries. Their sayings were collected and widely read. St Anthony the Great is the best known.
Docetism: The early belief that Christ only seemed to have a real human body and did not truly suffer. St Ignatius of Antioch wrote against it. From the Greek dokein, “to seem”.
Doctor of the Church: A title given by the Catholic Church to saints recognised for the importance of their teaching. Augustine, Athanasius, Basil, John Chrysostom and John of Damascus are among them. The Orthodox Church honours Basil, Gregory the Theologian and John Chrysostom as the “Three Holy Hierarchs and Universal Teachers”.
Ecumenical council: A gathering of bishops from across the Christian world to settle questions of belief, such as Nicaea (325) and Chalcedon (451).
Eucharist: The central sacrament of the Church, in which the faithful receive the true Body and Blood of Christ; celebrated in the Orthodox Church as the Divine Liturgy (in the West, the Mass). From the Greek eucharistia, “thanksgiving”.
Gnosticism: A modern name for various second-century movements that taught salvation through secret knowledge (gnosis) and often regarded the material world as evil. St Irenaeus wrote Against Heresies to answer them.
Heresy: A teaching that the Church judged to contradict its essential beliefs. From the Greek hairesis, “choice” or “faction”.
Hesychasm: A tradition of prayer in Eastern Christianity centred on inner stillness and the repeated Jesus Prayer. From the Greek hesychia, “stillness” or “quiet”.
Homoousios: Greek for “of the same essence”. The Nicene Creed uses it to say the Son is of one substance with the Father.
Icon: A holy image of Christ, Mary or the saints, painted in a traditional style and venerated in Christian worship, especially in the Eastern churches. St John of Damascus defended their use.
Iconoclasm: The eighth- and ninth-century controversy over destroying or forbidding holy images. The Second Council of Nicaea (787) upheld the veneration of icons.
Incarnation: The Christian belief that the eternal Son of God became human in Jesus Christ. From the Latin for “taking flesh”.
Liturgy: The public worship of the Church, especially the order of the Eucharist. From the Greek leitourgia, “public service”.
Logos: Greek for “word” or “reason”. In John 1:1 and the Fathers it names the eternal Son of God, the Word.
Manichaeism: A religion founded by Mani in third-century Persia that taught a struggle between two equal powers of light and darkness. Augustine followed it for some years before his conversion.
Martyr: Someone who is put to death for their faith. From the Greek martys, “witness”.
Monasticism: A way of Christian life withdrawn from the world and devoted to prayer, either alone or in community.
Nestorianism: A view associated with Nestorius, Archbishop of Constantinople (died c. 451), which was condemned at the Council of Ephesus (431) for dividing Christ into two persons and refusing to call Mary Theotokos.
Nicaea, Council of: The first ecumenical council, held in 325 at Nicaea (modern İznik, Turkey). It rejected Arianism and produced the first form of the Nicene Creed.
Nicene Creed: The statement of faith from the Councils of Nicaea (325) and Constantinople (381), still recited in many churches today.
NPNF (Nicene and Post-Nicene Fathers): A 28-volume English translation series edited by Philip Schaff and Henry Wace (1886–1900), Series 1: Augustine and Chrysostom. Series 2: Greek and Latin Fathers from the 4th to the 8th century, including Athanasius, the Cappadocians and John of Damascus. Several texts on this site come from it.
Orthodox: Meaning “right belief”. It describes teaching held to be true, and is also the name of the Eastern Orthodox Church.
Pascha: The feast of Christ’s Resurrection (Easter). From the Hebrew pesach, Passover.
Patristic: Relating to the Church Fathers. Patristics is the study of their lives and writings.
Pelagianism: The teaching associated with the monk Pelagius (c. 354 – c. 418) that human beings can avoid sin and live righteously by their own free will, without needing God’s grace. Augustine opposed it.
Presbyter: An elder of the early Church. The English word “priest” comes from it.
Septuagint: The Greek translation of the Hebrew Scriptures made before Christ. Most early Christians read the Old Testament in this version.
Theosis: The Christian hope of being united with God and sharing in his life by grace, also called deification. It is a major theme in Eastern Christian teaching.
Theotokos: Greek for “God-bearer”, a title for Mary affirmed at the Council of Ephesus (431). It expresses that the one she bore is God the Son made man.
Trinity: The Christian belief in one God in three persons: Father, Son and Holy Spirit.