I've decided to systematize what I've learned about Christianity over the past few years. So here's a collection of definitions of important terms, to help guide others along the road that I've come. Further helpful additions are welcome.
Anabaptist: the wife of John the Baptist.
Antichrist: what you call your parent's sister with the messianic delusions.
Archeology: the search for the ark and other relics.
Atonement: tuning the musical instruments in the church, especially as an official act or policy. For example, "The leader's belief in limited atonement caused much dissonance and lack of harmony in the church."
Babylon: what the preacher does every Sunday. Babylonian captivity: the forced endurance of a very long-winded preacher. The Old Testament has a great deal to say about the reasons that God inflicted this punishment on his people, and what can be learned through this process of suffering.
Bronze Age: the era before there was a gold and silver Olympic medal.
Canon: a piece of artillery used in the religious wars.
Cell group: 1) a small group of people who are forced to meet in a confined room as a punishment; 2) the marketing... er, uh... evangelism department of a church.
Charismatic Gifs: the pictures available from a television evangelist's web site.
Christian Right: the right of Christians to rule the United States, based on the claim that it was founded by Christians.
Church of the Holy Sepulchre: a wholly dead church.
Church planting: 1) planting something in the church garden; 2) by extension, digging a grave in the churchyard.
Cistern: the female counterpart to "brethren". The Bible speaks much of brethren and only occasionaly refers to cisterns, but archeological evidence confirms that cisterns were abundant in ancient Israel. Among other duties, they apparently had an important responsibility in providing liquid refreshments for meetings.
Court of the Gentiles: a courtyard in the temple, known for the unusual pattern of the tiles that covered it.
Court of the Men: an ancient basketball court.
Court of the Women: the procedure by which a man finds a wife.
Critical commentary: a commentary that you absolutely must own.
Cross-cultural mission: a mission to spread the culture of the Cross, i.e., western Christian Culture.
Deutero-Isaiah: colloquial among scholars for the dude who wrote the book of Isaiah, as in "The Deutero-Isaiah was righteous, man!"
Dispensationalism: what Jesus taught the rich young ruler.
Divided Monarchy: the state of Israel after Saul's head was severed from his body.
Election: when all the Calvinists get together to vote on whose doctrine is sound enough to be saved. [Thanks to Walter Jones for this one.]
Eschatology: a study of incredibly disgusting (scatalogical) things.
Evangelism: [from Latin "e-", out of, + "van" + "gel"] squirting gel toothpaste at unbelievers while driving around in the church van. Evangelism is often done by church youth groups.
Exegesis: the evil counterpart to Jesus. [Thanks to Shane Ross for this one.]
Exorcism: Jesus' workout method.
Exposit: [from Latin "ex", out of + "posit", place] to take out of context, to misquote.
Fasting: the practice of eating only fast food as a spiritual discipline.
Five-point Calvinist: an especially long-winded minister with five points in his sermon instead of the usual three.
Feast of booths: a time of mourning when the leather on furniture is eaten in memory of the siege of Jerusalem. Also sometimes known as the "Feast of Tabernacles" because of the practice of eating tent canvas.
Feast of lights: magicians eating fire as part of a liturgical celebration.
Feeding of the five thousand: a reference to the fate of the many previous victims of the lion's den before Daniel.
Fruit of the spirit: (1) wine or other fermented fruit products; (2) the result of such products.
Fundamentalism: of uncertain origin. Most definitions are supplied by its detractors: 1) a state of mind devoted to raising funds. 2) devotion to the "fundamental principles of the world" (Col 2:20; Gal 4:3), i.e., legalism.
Gift of healing: the divine enablement to serve as a cobbler.
Gloss: the final finishing touches the author put onto his book to make it look nice.
Graven images: pictures of tombs or graveyards. Prohibited in the ten commandments in order to keep the Israelites from being morbid.
Great Awakening: what happens after the sermon.
Great Commission: Adam's sin.
High Church: a chapel high in the mountains, known typically for the simple style of worship practiced because of the rustic conditions.
Higher critics: parishoners seated in the balcony.
Host: tasteless predecessor to today's Hostess twinkies; formerly served weekly in churches.
Incarnation: 1) what the US is during rush hour; 2) the anthers, stamens, and other parts of a carnation within the carpals.
Inflect: to punish by verbal abuse, as in "When the professor realized how much his lazy students' knowledge of Greek was declining, he inflected even more nouns upon them."
Intertestamental period: the punctuation mark at the end of the last sentence of Malachi.
Magnificat: the name of Mary's pet cat. Mary composed a beautiful ode to the cat which in Latin begins, "Magnificat anima mea..." (Magnificat, my [pet] animal...)
Olivet discourse: contents of one of the courses of the Last Supper.
Paleolithic culture: the culture that produced the earliest known lithographs.
Passover: one of the principle feasts of the Jews, so named because one of the most common statements at the table is "Pass over the...."
Paradise: what the Roman soldiers used to gamble for Jesus' clothing.
Pastoral epistles: letters extolling the beauty of the countryside.
Paraclete: the shoes we wear when we "run the race for the prize of the high calling of God"; the feet "shod with the preparation of the gospel of peace".
Pauline epistles: writings of Pauline, a deaconess in the early church.
Pentecost: one of the main feasts of the Jews, so named because everything was five times its normal cost due to the influx of visitors.
Pharisee: ["far"+"see", same origin as German "Fernseher" and Latin "tele-vision"] a special device for observing sin at a distance.
Pilgrim's Progress: the ship's log on the Mayflower.
Pillar of the church: the term used in the Bible to refer to Simon Styletes, the ascetic who lived for years on top of a pillar.
Plymouth brethren: a society of Christians who own Chryslers. Sometimes their detractors have accused them of not being in one Accord.
Post-millenialist: a survivor of the Y2K crisis.
Post-modernism: a movement to modernize the postal system.
Q: the manuscript that told Jesus when to come on stage.
Rapture: getting especially emotionally excited about God, such as often happens during prophecy conferences.
Republican: a publican who repents and then backslides.
Romans, epistle of: the only extant love letter of St. Paul.
Sanctification: the brewing of Sanka, an early brand of decaffeinated coffee, for the coffee hour after the service.
School of the prophets: an ancient Hebrew business school.
Syntactic: a tactic for sinning intelligently to avoid getting caught, as in "The foul-mouthed boy was not rebuked until he made a syntactic error."
Seven Seals: a troop of performing seals which gives shows in the glassy sea (a large aquarium).
Song of Degrees: Hymn #360 in the old hymnal.
Song of Ascent: a song that a street musician in the old days would play for penny.
Third use of the law: the third reading of the words of Jeremiah, when Jehoiakim used the scroll as fuel for the fire. The validity of this use of the law is much debated in Reformed circles.
Tigris: one of the beasts in the lion's den.
Toronto blessing: "May the Lord bless you as he blessed the Blue Jays...."
Typology: a method of determining hidden meanings in Old Testament texts by looking at the type faces. For example, we discern that the crossing of the Red Sea is related to baptism (1 Cor. 11) because it's written in a baptismal font.
Virgin birth: how each new Bible version comes out into the world after it has been conceived.
White throne judgement: the process Solomon went through to choose a new throne.
Ziggaraut: something which the Babylonians smoked during their New Year festival.