I was raised in a denomination that did not use images and symbols.  This page, like much of this site, is the attempt of a fellow from a Church that did not value Church tradition to come to grips with parts of it.  Many of the symbols are not at all clear to the unschooled largely because they are from another time. That being the case they connect our Chrsistian present to the past.  Further many an explanation requires a short dance through Latin and Greek. Those dances are offered with much of the choreography lifted from others. 

The issue of images generally was settled to the contentment of most Catholics in 787 at the Seventh Ecumenical Council but reopened largely by the Puritans at the reformation.  In 787 it was called the Iconoclast controversy.  The problem is when does a symbol become an idol. That is actually a matter of heart -- not art, but we will leave that, along with the torches and angry mobs, to the side here.

On this page we will look at two classifications of symbol:  Those what stand for Christ and those that illustrate the Trinity. 

Jesus

There are no actual recorded images of Jesus, but as we know images are controversial in any case.  (The portraits of Jesus we see today did not come into their more or less standard form until the 6th century.)  Those would need no explanation in any case.  What can use some decoding are the symbols in the following tables.

Symbol Name Description
agnusdei-standing-wegast-50 Agnus Dai

Agnus Dei is Latin for Lamb of God.  This title for Jesus appears in the Gospel of John, with the exclamation of John the Baptist: "Behold the Lamb of God who takes away the sins of the world" (John 1.29) and 'When he saw Jesus passing by, he said, “Look, the Lamb of God!”' (John 1.26).

You will see this sort of image adorning banners and windows in Churches from a variety of traditions.

Agnus Dei is also the name of a prayer:

Lamb of God, who take away sins of world, 
have mercy on us.

Lamb of God, who take away sins of world, 
have mercy on us.

Lamb of God, who take away sins of world, 
grant us peace.

alpha-omega-50 Alpha and Omega

The term Alpha and Omega comes from the phrase "I am the alpha and the omega," it is used as an appellation for Jesus in the Book of Revelation (verses 1.8, 21.6, and 22.13).

Alpha is the first letter of the Greek alphabet and Omega is the last.  The notion, as applied to Jesus is that He is the beginning and the end of all things.

chi rho clipart-50 Chi Rho The Chi Rho symbol is a Christogram formed from the first two Greek letters of the word "Christ" (Greek: ΧΡΙΣΤΟΣ). 

The labarum (Greek: λάβαρον) was a vexillum (military standard) that displayed the "Chi-Rho" symbol that was used by the Roman emperor Constantine I.  Since the vexillum consisted of a flag suspended from the crossbar of a cross, it was ideally suited to symbolize the crucifixion of Christ. 

fish ixoye clipart-50 Ikthus

Also spelled Ichthus, Ichthys or sometimes Ikhthus, from Koine Greek:  ΙΧΘΥΣ which actually means fish.  The fish symbol has been used as a Christian symbol since the first century.  It is an acronym as follows:

 

Greek

Translation
Letter Word Transliteration
Ι (Iota) Ιησούς Iēsous Jesus
Χ (Chi) Χριστός CHristos Christ
Θ (Theta) Θεού THeou God's
Υ (Upsilon) Υιός hUios Son
Σ (Sigma) Σωτήρ Sōtēr Savior

 

The story I learned in my youth was that this symbol was used by Christians during the first century persecutions to identify each other.  (This story is confirmed by Wikipedia.)  Various forms of the Ikthus were found in the catacombs.

Because a fish symbol is so generic it has been easy for some these days to claim that it is of pagan origin by pointing to its use by earlier religious cults.  Further, today we see it parodied as a fish with feet  and the name Darwin inscribed.  For more on this see Ikthus Wars

ihs-wegast-50 IHS

IHS or IHC is a Christogram that is transliterated from Greek, specifically it consists of the first three letters of the Greek name of Jesus (Ἰησοῦς), iota-eta-sigma, or ΙΗΣ. The Greek letter iota is rominized with I, and the eta with H, while the Greek letter sigma is either C or S, as can bee seen in the Greek above.  Also note that there is an accident of Greek script where a final sigma takes a form that can look more like a C. Because in the Latin-alphabet letters I and J were not systematically distinguished until the 17th century, "JHS" and "JHC" are equivalent to "IHS" and "IHC".

There are several backronyms that are used with this symbol which include:

Iesus Hominum Salvator ("Jesus, Savior of men" in Latin)
I Have Suffered
In His Service

IHS is seen monogrammed and stylized in many ornate ways.

inri-wegast-50 INRI INRI is often seen on crucifixes, it is an acronym of the Latin inscription IESVS·NAZARENVS·REX·IVDÆORVM, which translates to "Jesus the Nazarene, King of the Jews".  This refers to what Pilate wrote as the title of Jesus in the Gospels.

 

The Trinity

The concept of the Trinity is difficult for those inside the Church to understand and a stumbling block for those outside of it. Many of the symbols used in the Church are attempts to represent the trinity or at least remind us of it.

The English word Trinity is derived from Latin Trinitas. Trinitas comes from trinus (three each, threefold, triple), and the word unitas from unus (one). Tertullian, a Latin theologian of the early 3rd century, is credited with coining the word Trinitas, that became our word "Trinity."  He also used the word "person" and "substance" to explain that the Father, SShield-Trinity-Scutum-Fidei-Englishon and Holy Spirit are "one in essence—not one in Person".

About a century later, in 325, the First Council of Nicaea established the doctrine of the Trinity as orthodoxy and adopted the Nicene Creed, which described Christ as "God of God, Light of Light, true God from true God, begotten, not made, being of one substance (homoousios) with the Father, through whom all things were made."

On the right is the Scutum Fidei or "Shield of the Trinity" which is a diagram that is meant to be helpful.  It must be emphasized this it is not intended to be a sort of "schematic of God" rather it is to emphasize that the persons of the trinity are separate.  The origin of the shield is uncertain but it seems to be part of the 12th century attempts to explain the concept of the Trinity. The problem of explaining that three are one and one is three remains today (even the grammar gets sketchy).  The following symbols represent just that, none of them do justice to the concept.

Symbol Name Description
trefoil-wegast-50 Trefoil The trefoil has three lobes yet is one figure.  It is probably an abstraction of some of the symbols below.
triangle clipart-50 Triangle The triangle has three side and three corners, yet it is one figure.
Trefoil and triangle interlaced. A trefoil combined with an equilateral triangle was also a moderately common symbol of the Trinity during the late Middle Ages in some parts of Europe.  We see various forms of it today.
triquerta 2 clipart-50 Triquerta Triquerta is derived from the Latin tri- ("three") and quetrus ("cornered"). Its original meaning was simply "triangle" and it has been used to refer to various three-cornered shapes. Nowadays, it has come to refer exclusively to the particular more complicated shape pictured here.  It is formed of three vesicae piscis, the shape made by the intersection of two circles.  Sometimes there is an added circle in or around it.   Some sources say that it is of Celtic origin.  Some say it is based on three fish.  Sometimes it is seen with fish tales.  It is also possible to pull it out of the symbols below.
240px-BorromeanRings-Trinity Borromean Rings

In mathematics, the Borromean rings consist of three topological circles which are linked and form a Brunnian link, removing any ring results in two unlinked rings.  In this rendition you can see that the circles cannot be in the same plane because of the patch were the intersections would have been.  This is not a Venn Diagram from logic or set theory but a two dimensional representation in something three-space. 

This figure is from Wiki Commonswhich indicates that it is from a 13th century manuscript. The Latin on the figure that you probably cannot read on this version is "tri-ni-tas" in its three syllables, in the three rings and "unitas" in the center.

The idea is that removing or diminishing one of the rings renders our whole concept of God incorrect.  Many early heresies did just that, largely in their thinking about Christ.

TrinityShield Venn Diagram Projecting the Borromean Rings into a two dimensional space does produce a Venn Diagram.  Most often this is seen without the labels.  The three letters in the circles represent the Latin; Pater(Father), Filius (Son), and Spiritus Sanctus (Holy Spirit). Deus is, of course, God.

 

Christian Symbol links

 http://www.christiansymbols.net/ 5/4/13

 http://www.religionfacts.com/christianity/symbols.htm 5/1/13

Footnotes:

 bakronim BAK-ro-nim]
-noun
A word re-interpreted as an acronym.

 Christogram [kris-tuh-gram]
–noun
a symbol of Christ, especially the Chi-Rho.