100 Most Important Terms in Christian Theology

Christian theology is rich and diverse, encompassing centuries of thought, debate, and revelation. The following is a list of 100 crucial terms in Christian theology (for both Protestants and Catholics), each accompanied by a brief definition or explanation to illuminate its significance within the Christian tradition.

1. Trinity The belief in one God in three persons Father, Son, and Holy Spirit, coexisting eternally in a single divine essence.

2. Incarnation The doctrine that the Second Person of the Trinity, the Son, took on human flesh in the person of Jesus Christ.

3. Atonement The reconciliation between God and humanity achieved through Christ’s sacrificial death and resurrection.

4. Justification The act of God declaring a sinner righteous by faith in Jesus Christ, apart from works.

5. Sanctification The process of being made holy, involving a believer’s growth in righteousness and moral transformation through the Holy Spirit.

6. Salvation Deliverance from sin and its consequences, granted by God through faith in Jesus Christ.

7. Eschatology The study of the last things, including beliefs about the end times, the Second Coming of Christ, and the final judgment.

8. Sacraments Holy rites instituted by Christ that convey grace, including baptism and communion in most Christian traditions.

9. Grace The unmerited favor of God towards humanity, central to understanding salvation and God’s actions in the world.

10. Faith Trust or belief in God and the doctrines of Christianity, seen as a gift from God and a means by which believers receive salvation.

11. Gospel Literally “good news,” referring to the message of salvation through Jesus Christ’s life, death, and resurrection.

12. Redemption The action of Jesus Christ by which humanity is freed from sin through His sacrificial death.

13. Original Sin The doctrine that all humans inherit a sinful nature due to the disobedience of Adam and Eve.

14. Predestination The belief that God has foreordained all events and outcomes, including the eternal destinies of individuals.

15. Revelation The act of God making Himself and His will known to humanity, through Scripture and Jesus Christ.

16. Canon The collection of books that constitute the authoritative Scripture of the Christian faith.

17. Heresy Beliefs or practices that go against the accepted doctrine of the Church and challenge its core teachings.

18. Orthodoxy Adherence to the established or traditional beliefs of Christianity, as opposed to heresy.

19. Creed Formal statements of Christian beliefs, such as the Nicene Creed, used to summarize and affirm core doctrines.

20. Apostasy The act of renouncing or abandoning one’s faith.

21. Evangelism The preaching or sharing of the gospel with the aim of converting others to Christianity.

22. Martyr An individual who suffers death for their faith in Christ, witnessing to the truth of Christianity.

23. Doctrine Formal teachings or beliefs held and taught by the Church.

24. Ecclesiology The study of the Church, its nature, functions, and structure.

25. Liturgy The prescribed form of worship in Christian tradition, including the sacraments and other rites.

26. Dogma Fundamental beliefs defined by the Church as essential to Christian faith.

27. Sin An act or condition that goes against God’s will and law, separating humans from God.

28. Imago Dei Latin for “image of God,” the belief that humans are created in God’s image and likeness.

29. Transubstantiation The belief in some Christian traditions that, in the Eucharist, the substances of bread and wine become the body and blood of Christ, while retaining their accidental properties.

30. Soteriology The study of salvation, including its nature, means, and scope.

31. Christology The study of the person and work of Jesus Christ.

32. Apologetics The defense of Christian faith against objections and misinterpretations.

33. Pneumatology The study of the Holy Spirit, His nature, and work in the world and in believers.

34. Covenant A solemn agreement between God and humans, involving mutual commitments and promises.

35. Parousia The Second Coming of Christ, anticipated in Christian eschatology.

36. Exegesis The critical interpretation of biblical text, aiming to uncover its intended meaning.

37. Pentecost The event where the Holy Spirit descended on the apostles, marking the birth of the Christian Church.

38. Iconoclasm The rejection or destruction of religious images on the basis that they constitute idolatry.

39. Monasticism A religious way of life that involves renouncing worldly pursuits to devote oneself fully to spiritual work.

40. Asceticism Strict selfdiscipline and avoidance of all forms of indulgence, typically for religious reasons.

41. Ecumenism The movement promoting unity among Christian denominations.

42. Charisma A gift of grace, often referring to spiritual gifts endowed by the Holy Spirit.

43. Discipleship The process of following Jesus Christ and becoming conformed to His teachings and life.

44. Theodicy An attempt to justify God’s goodness in the presence of evil and suffering in the world.

45. Kerygma The core teaching or proclamation of the Christian gospel.

46. Missiology The study of Christian mission and the spread of the gospel across cultures.

47. Sanctuary A sacred place of worship in Christian tradition.

48. Sabbath A day of religious observance and abstinence from work, kept by Christians as a rest day.

49. Tithing The practice of giving a tenth of one’s income to the Church.

50. Iconography The use and interpretation of religious images in Christian art and worship.

51. Kenosis The selfemptying of Jesus’ own will to become entirely receptive to God’s divine will.

52. Gnosticism An early Christian heretical movement that taught salvation through secret knowledge.

53. Homiletics The art of preaching or writing sermons.

54. Mariology The study of the life, role, and veneration of the Virgin Mary.

55. Messianic Expectation The anticipation of the coming of a Messiah, fulfilled in Jesus Christ according to Christian belief.

56. Providence God’s continuous involvement with all created things, guiding them toward their ultimate purpose.

57. Apostolic Succession The uninterrupted transmission of spiritual authority from the apostles through successive popes and bishops.

58. Beatific Vision The direct knowledge and experience of God enjoyed by the blessed in heaven.

59. Canonization The process by which the Church declares a deceased person to be a saint, included in the canon, or list, of recognized saints.

60. Catechesis Religious instruction and formation in the major elements of Christian faith.

61. Consubstantiation A theological perspective that Christ is present “in, with, and under” the elements of bread and wine in the Eucharist.

62. Deification (Theosis) The process by which believers become more like God in their life and being, through grace.

63. Eschaton The final event in the divine plan; the end of the world.

64. Hagiography The writing of the lives of saints.

65. Imputation The crediting of Christ’s righteousness to believers, on the basis of faith.

66. Millenarianism The belief in a future golden age of peace, justice, and prosperity, often in connection with the Second Coming of Christ.

67. Mysticism The pursuit of a direct, personal experience of the divine, often through contemplative and meditative practices.

68. Patristics The study of the early Christian writers known as the Church Fathers.

69. Perichoresis A term describing the interpenetration and indwelling of the three persons of the Trinity in one another.

70. Propitiation The appeasement of God’s wrath and justice by the sacrificial death of Christ.

71. Regeneration The spiritual rebirth of a person through the working of the Holy Spirit, associated with salvation.

72. Relics Physical remains or personal effects of saints, venerated for their association with the holy.

73. Schism A formal division within or split from the Christian Church, often due to theological or political disagreements.

74. Simony The buying or selling of ecclesiastical privileges, such as pardons or benefices.

75. Syncretism The amalgamation of different religions, cultures, or schools of thought, often seen negatively in Christian theology.

76. Transcendence The aspect of God’s nature and power which is wholly independent of the material universe, beyond all physical laws.

77. Veneration The act of honoring a saint, angel, or holy person through acts of respect and devotion.

78. Witness The act of giving testimony of one’s faith and experience of God through words and deeds.

79. Worship The act of showing reverence and adoration for God, typically through rituals, prayers, and songs.

80. Zion Biblically, the hill of Jerusalem on which the city of David was built, symbolizing the spiritual and eternal city of God.

81. Apostolic Pertaining to the apostles or their teachings, traditions, or era.

82. Biblical Inspiration The doctrine that the authors of Scripture were guided by the Holy Spirit, ensuring their writings are the authoritative Word of God.

83. Calvinism A theological system based on the teachings of John Calvin, emphasizing sovereignty of God, predestination, and grace.

84. Dispensationalism A theological framework that interprets history as divided by God into dispensations, each with a different method of salvation.

85. Eucharistic Adoration The practice of praying before the consecrated Eucharist, affirming belief in the real presence of Christ.

86. Fundamentalism A movement within Protestantism upholding a literal interpretation of Scripture and strict adherence to basic Christian doctrines.

87. Hypostatic Union The doctrine that in Jesus Christ, one person subsists in two natures, divine and human, without division or confusion.

88. Infallibility The belief that the Church, under certain conditions, is preserved from error in teaching on matters of faith and morals.

89. Liturgical Year The calendar used by the Church to commemorate the mysteries of Christ’s life, from Advent through Christ the King.

90. Monergism The doctrine that the Holy Spirit is the only effective agent in regeneration, emphasizing the primacy of divine action in salvation.

91. NeoOrthodoxy A 20thcentury theological movement emphasizing the transcendence of God and the centrality of the Bible as divine revelation.

92. Pelagianism A heretical belief that original sin did not taint human nature and that mortal will is still capable of choosing good or evil without special divine aid.

93. Postmillennialism The belief that Christ will return after the millennium, a golden age of Christian dominance and societal perfection.

94. Premillennialism The belief that Christ will return to earth and then reign for a thousand years before the final judgment.

95. Real Presence The belief that Jesus Christ is truly present in the Eucharist, not merely symbolically or metaphorically.

96. Reformation A 16thcentury movement for the reform of abuses in the Roman Catholic Church ending in the establishment of the Reformed and Protestant Churches.

97. Revivalism A movement within Christianity aimed at revitalizing faith and devotion among believers through impassioned preaching and public events.

98. Sola Fide A Reformation principle meaning “by faith alone,” affirming that justification comes through faith in Christ, not by works.

99. Sola Scriptura A foundational Protestant principle meaning “Scripture alone,” asserting the Bible as the sole infallible source of authority for Christian faith and practice.

100. Universalism The theological belief that all people will eventually be saved and reconciled with God, emphasizing God’s love and mercy over His justice.

These terms represent the breadth and depth of Christian theological thought, reflecting centuries of reflection, debate, and experience in the Christian tradition. Understanding these concepts is crucial for anyone seeking to deepen their grasp of Christian theology and its implications for faith and practice.