| Index of Catholic Terminology |
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I
ICHTHYS: An acronym meaning "fish" in Greek. From the many titles of Jesus, three emerged as the favorites of believers: Christ (Gk: "anointed"), Son of God, and Savior. These three would easily combine, becoming a creed and a prayer (see the Jesus Prayer). In Greek, the holy name of Jesus, plus these three titles, would read: Iesous Christos Theou Yos Soter (Jesus Christ, Son of God, Savior).
Icon:A picture of Christ, Mary or the saints, painted in the style of the Eastern Church. Often on wood and adorned with precious stones.
Iconoclasm: The heresy which condemned any use of statues or other representations of Christ, Mary, the angels, or saints.
Iconostasis: Large, wooden screen painted with icons which separates the nave from the sanctuary in most Eastern Rite churches.
IHS or IHC: In Greek, the first three letters of the name of Jesus Christ in Greek capital letters: IHCOUC (the older form of the Greek sigma, S, resembling our C). In art, St. Ignatius Loyola is sometimes pictured with this monogram, alluding to his fabled miraculous knowledge of the Trinity.
Immaculate Conception: Catholic dogma concerning Mary and the name of a feast in her honor celebrated Dec. 8. It refers to the belief that Mary was without sin from the moment she was conceived.
Impediments to Marriage:Something which prevents a person entering into a Church marriage. For example, certain degrees of blood-relationship between partners, or where one partner is not baptized. A dispensation can be obtained from some impediments.
Incarnation:A theological term for the Son of God becoming man in the person of Jesus Christ.
Incense: Incense (material used to produce a fragrant odor when burned) is used as a symbol of the Church’s offering; the rising smoke represents the prayers of the assembly rising to God. Symbolic in its burning (zeal, fervor), its fragrance (virtue) and its rising smoke (acceptable prayer, as noted in Psalm 141.2). See frankincense.
Index of Forbidden Books: A now defunct catalog of books which the Church forbade Catholics to read or own.
Indulgences:Remission of the punishment of penance due to sin after its guilt has been forgiven. By virtue of the authority given it by Christ, the Church may grant those who have received forgiveness of their sins a share in the merits of Christ and the saints so that the burden of punishment their sins deserve may be removed or lightened. To gain an indulgence Catholics must be free from serious sin and must carry out prescribed good works, or recite certain prayers
Infallibility: The ability of the pope or the bishops in union with the pope to speak officially without error in specific circumstances concerning morals and faith.
Inquirer: Describes a person in the first stage of the process of Christian initiation.
Inquisition: An institution of the Church charged with the eradication of heresies.
INRI: Latin abbreviation of Iesus Nazarenus Rex Iudaeorum (Jesus of Nazareth, King of the Jews) over Jesus' cross (Jn 19.19). (A slightly-curved horizontal line over the letters indicates abbreviation.)
Intercession:The prayers the saints in heaven offer to God on behalf of the people on earth who request their help
Intercommunion: The agreement or practice of two Ecclesial communities by which each admits members of the other communion to its sacraments.
Israelites: The Jewish people; commonly used term in the Old Testament