abbot (< Hb/Aramaic abba, "father") -- pope (< Gk papa, "father"; originally an honorific used of any respected member of the Church hierarchy, esp a bishop)
agnostic/agnosticism ("having no hidden knowledge") -- atheist/atheism ("having no god," a charge levelled at many early Christians -- as well as at people like Socrates & many sophists)
St Ambrose of Milan
St Antony -- hermit (< Gk eremos, "desert")-- Pillar Saints
apocalypticism
Apostles (Gk "messangers") -- Apostolic succession
Aramaic
Arianism -- Montanism -- Donatism -- Pelagianism
asceticism (< Gk askesis, "[athletic] training," "practice") -- celibacy -- monasticism (cf. monk)
St Augustine of Hippo -- Confessions -- City of God -- doctrine of grace -- doctrine of sacramentality
baptism
basilica
bishop (< Gk episcopos, "overseer") -- priest (< Gk presbyteros, "elder") -- deacon
breviarum ("abbreviation," "condensation," "epitome") -- Corpus Iuris Civilis (CIC; "the body of civil law")
Byzantium -- Byzantine
canon (Gk "measure," "standard") -- canonical books (of Scripture)
catholic (Gk "universal") -- ecumenical (Gk "general") -- orthodox (from Gk orthodoxia "correct belief") -- heterodox (< Gk heterodoxia "different belief"; cf. heresy) -- ecclesia (Lat "community," "church / the Church")
Christ (Gk "annointed one"; cf. Messiah, from Hb Mashiah with the same meaning)
Constantine the Great -- Eusebius -- Theodosius I -- Theodosius II
Constantinople
Council of Nicaea
creed (< Lat credo, "I believe") -- Nicene Creed
Danube -- Dacia
Diocletian -- colonus (pl. coloni; farmers tied to the soil) -- tetrarchy ("government of four") -- Augusti -- Caesari -- consistory -- Constantine -- Milvian Bridge (battle) -- Constantinople ("Constantine's polis")
doctrine (< Lat doctrina, "teaching") -- orthodoxy (Gk "correct views" < doxa, "opinion") -- heterodoxy ("other views")
excommunication
gentile (< Lat gens, "people," "nation") -- Jew
Germanic
Gnostic (< Gk gnosis, "secret")
Gregory I "the Great"
Heavenly Jerusalem
heresy (Gk "choice," "individual selection") / heretical -- heterodoxy /heterodox
St Jerome -- Vulgate
Jewish revolt
Judaea -- Galilee
Julian the Apostate
Late Antiquity
Latin -- Romance languages
lay / laity -- secular (< L saeculum, "the world") -- ecclesiastical ("having to do with the ecclesia") / religious -- clergy -- secular clergy
love feast (Gk agapê) -- Mass -- Lord's supper -- Eucharist -- (sacrament of) communion
martyrion -- martyr (Gk "witness") -- athletes of Christ (cf. asceticism)
monk (Gk monachos, related to monos, "solitary"; cf. asceticism) -- coenobitic monasticism -- ora et labora (Lat "pray & work")
monotheism
mystery religions [sometimes also referred to as mystery cults]
Old Testament -- New Testament -- Gospel
Original Sin -- felix culpa (Lat "the happy sin")
patristic ("fatherly"; often used in combinations like "patristic author," "patristic period," etc.) -- Fathers of the Church
Paul/Saul of Tarsus
St (Vibia) Perpetua
persecution
Philon of Alexandria (a.k.a. Philo judaeus) -- Neoplatonism
polytheists ("followers of many gods") -- pagans (< L pagus, "countryside") -- heathens (< Gk ethnos, "people"; cf. gentile)
relic -- icon
religion: cultic practice -- beliefs -- piety
Romulus Augustulus -- Odoacer [sometimes also spelled Odovacer]
sacrament (from Lat sacramentum, "oath," "pledge")
Scripture -- fourfold interpretation (literal/historical, "what happened"; allegorical, "what does it mean"; tropological/moral, "what to do about it"; anagogical, "what to aspire to")
Symmachus (Aurelius Symmachus)
synagogue -- rabbinical Judaism -- Jerusalem Temple [Herodian Temple destroyed in Great Revolt, 70 AD]
Tertullian
Virgil -- Aeneid
Visigoths