Anno Domini, or "Year of Our Lord". This is used to indicate a date that occurred after Christ's birth, such as "A.D. 1976". Note that the "A.D." comes before the date, not after.
Ave Maria, or "Hail Mary"
Ad Majorem Dei Gloriam, or "For the greater glory of God." This is the Jesuit motto, beloved by St. Ignatius of Loyola.
"Athanasius against the world."
Before Christ (see "A.D."). While "A.D." comes before the date, "B.C." comes after the date, ex. one writes "A.D. 1976" but "242 B.C."
"To bless, to praise, to preach." One of the mottoes of the Dominican Order.
Bonae Memoriae, or "Of Happy Memory"
Blessed Virgin Mary
Christus A.O.M.P.S. Defendit Christus Ab Omni Malo Plebem Suam Defendat
Christ is risen! This greeting is used during the Easter Octave. The response is "Vere resurrexit" ("He is risen indeed!").
Christ conquers, Christ reigns, Christ commands
"To Contemplate and hand on to others the fruit of our contemplation." One of the mottoes of the Dominican Order.
"Crux sacra sit mihi lux" (Holy Cross be my light). This appears on the St. Benedict Medal.
"My God and My All." Motto of the Franciscan Order.
"God is not mocked"
"God wills it!" Motto of the Crusades.
Dei Gratia, or "By the Grace of God"
Dominus Noster, or "Our Lord"
Dominus Noster Jesus Christus, "Our Lord Jesus Christ"
The Lord be with you (plural "you"). These words are sung many times by the priest during the Mass. The choir's response to them is "Et cum spiritu tuo," which means "And with thy spirit." If you want to tell a single person "May the Lord be with you, the form would be "Dominus tecum."
Deo volente, or "God willing"
"Behold the Lamb of God." St. John the Baptist's words. The full phrase is "Ecce Agnus Dei qui tollit peccata mundi" (Behold the Lamb of God Who takes away the sins of the world). These words are said at Mass after the Consecration, when the priest holds up the Blessed Sacrament for us to adore. See John 1:29.
"Behold the Man." These are the words of Pontius Pilate as he presents Our Lord, crowned with thorns, to the crowd. See John 19:5.
The letters stand for "Ex voto" and denote a votive offering.
"Outside the Church there is no salvation." Often abbreviated "EENS" in Catholic discussion groups.
Felicis Memoriae, or "Of Happy Memory," written after the name of a dead person, e.g. "John Smith, Fel. Mem."
"Glory to God in the highest." These are the words of the angels announcing the Nativity to the shepherds. The full phrase is "Glory to God in the highest: and on earth peace to men of good will."
"We have a Pope!" Said after a new Pope is elected.
His Holiness (referring to a Pope)
Jesus Christ (from the Greek)
Monogram of Jesus's Name. Many believe the letters mean "Iesus Hominum Salvator" ("Jesus Saviour of Men") or "In His Service." These are false interpretations, but common nonetheless. This monogram is iconographically associated, too, with St. Bernardine of Siena, St. John Capistran, St. Vincent Ferrer, and the Jesuit Order. Sometimes also written as "IHC" or "JHS."
"In this sign you will conquer." This is the Latin translation of the Greek words, TOUTO NIKA, seen by Constantine in his vision, along with the Chi-Rho.
"Iesus Nazarenus Rex Iudeorum" -- "Jesus of Nazareth, King of the Jews." This was the sign placed on the top of Jesus' Cross. See Matthew 27:37, Mark 15:26, Luke 23:38 and John 19:19.
in partibus infidelium, or "among the infidels"
In Christo, or "In Christ"
"May Jesus with Mary be with us on the way." One of Christopher Columbus's favorite prayers.
"Jesus, Mary and Joseph." You will find this most often written, centered, on the tops of correspondence, articles, essays, etc., sometimes with the letters separated by Crosses. Catholic schoolchildren write the initials of the Holy Family across the top of their homework papers.
Lord, have mercy (Greek). This phrase, combined with "Christe eleison" and sung nine times in the traditional Mass, is the only Greek to be found in the Latin Mass.
"Praise be to Jesus Christ!" This is an indulgenced Christian greeting. The response is "In aeternum!" ("For evermore!")
"A bad law is no law" (St. Thomas Aquinas)
"Through my fault, through my fault, through my most grievous fault." These words are part of the Confiteor at Mass, and were spoken as one beats one's breast three times in penance.
Greek acronym for "Meter Theou" or "Mother of God." Often seen in icons.
Notre Dame, French for "Our Lady"
Greek for "Victor." Often seen in icons along with "IC XC" to indicate "Jesus Christ, Victor"
"Touch Me not." These are the words of Jesus to Mary Magdalen after He rose from the grave. See John 20:17.
"I am not worthy." The words come from the prayer of the Roman centurion, and are said at Mass before receiving Communion. The full prayer is "Dómine, non sum dignus ut intres sub tectum meum, sed tantum dic verbo, et sanábitur ánima mea." (Lord, I am not worthy that Thou shouldst enter under my roof, but only say the word, and my soul shall be healed."). See Matthew 8:8 and Luke 7:6.
"Prayer and Work." One of the mottoes of the Benedictine Order and of the Trappists.
Pray for us (addressing one person, as in "Maria, ora pro nobis"). To address more than one person, use "Orate pro nobis," as in "Maria et Ioseph, orate pro nobis."
Greek for Christ's title "The One Who Is" or "I am" (Exodus 3:14, Apocalypse 4:8). Pronounced "Oh own." Often seen in icons.
Peace. One of the mottoes of the Benedictine Order.
Peace of Christ
Peace and all Good
"Peace be with you" (plural). The singular would be "Pax tecum."
"Through the Mother to the Son." The motto of the Marianist
"Where are You going?" These are the words of Pope St. Peter to Jesus, according to a legend. St. Peter tried to flee his persecution in Rome, but met Jesus on the Appian Way. He asked Him, "Dómine, quo vadis?" (Lord, where are You going?). Jesus answered, "Eo Romam iterum crucifigi" (I go to Rome to be crucified anew). There is a church there today that marks the spot where this is said to have happened. The church is named "Chiesa di Santa Maria in Palmis," but is better known as "Chiesa del Domine Quo Vadis" or simply the "Quo Vadis Church."
"The Remnant shall return!" This saying applies to the Truth that throughout History, a remnant has always remained faithful to God in spite of the corruption and lapses into paganism of their leaders
Requiescat In Pace, or "May he or she rest in peace." The plural is "Requiescant in pace" ("May they rest in peace").
causa finita est
"Rome has spoken, the matter is finished." Indicates that the decision is final and there will be no additional discussion.
"St. Anthony Guide." This short prayer asking St. Anthony to guide a correspondence to its destination is written on the backs of letters and envelopes, etc., and is often used in wax seals, ink stamps, and the like. It stems from St. Anthony's intercession, in A.D. 1729, in the case of a woman whose merchant husband had gone from their home in Oviedo, Spain to Peru on business. The wife had written her spouse letters, but received no reply. She then asked St. Anthony to intercede for her. Trusting completely in the power of God working through His most faithful St. Anthony, she wrote a letter to her husband and took it to Oviedo's Fransiscan church to place it in the hands of St. Anthony's statue, asking that the Saint see to it that her husband got the letter. She returned to the church later to find a reply from her husband and several gold pieces in the statue's hands. The husband's letter noted that he received the wife's letter from the hands of a Franciscan priest.
Servus Dei, or "Servant of God"
"Thus passes the glory of the world." A reminder of mortality and the importance of storing up treasure in Heaven rather than earth. This phrase is repeated to newly-elected Popes just before their first Papal Mass in order to keep themm focused on what is important and to remind themm that, though they are the Vicars of Christ, they are just men.
That God may be glorified in all things (Ut In Omnibus Glorificetur Deus). One of the mottoes of the Benedictine Order.
"For the City (Rome) and the world." When these words are found in a papal document, it means that the document is meant not only for Rome, but for the entire world. These words are also the name of a papal blessing given from the balconies of major Roman basilicas at solemn occasions, such as papal coronations, the annual Easter blessing, etc.
Truth. One of the mottoes of the Dominican Order.
"Votum Fecit Gratiam Accepit" -- "Vow made, graces received." The abbreviation for this phrase is often seen on votive offerings.
Long live the Pope! (Italian)
"With Zeal have I been Zealous for the Lord God of Hosts." The motto of the Carmelite Order.
Cross character made thusly:
Turn Number Lock (Num Lock) Key on, press ALT key and hold down while typing 0134 on your Number Pad (the HTML is: † )
Greek Cross, made by a plus sign. (See above entry, too).
The Pope emoticon, made with a plus sign, a dash, left parenthesis, colon, dash, and right parenthesis