Ask Father...: 'Catholic' vs. 'Apostolic,' anyone?

Two weeks ago, in place of my regular Sunday homily, I gave a brief catechesis on the new translation of the Nicene Creed, which is to take effect on the First Sunday of Advent, November 27, 2011.  Hopefully most people's questions were answered.  However, one parishioner asked the following question:

What is the difference between "Catholic" and "Apostolic"?

In order to get a little context, let's look at the full phrase:

I believe in one, holy, catholic, and apostolic Church.

 These four qualities--one, holy, catholic, and apostolic--are commonly known as the four "marks" of the Church.  We call them "marks" because they define the Church, and because a Church, in the truest definition of the word, is easily identifiable insofar as it conforms to these four marks.  They are effectively the standard by which true churches (and not ecclesial communities) are defined.  Let's look at all four of them.

One

Jesus giving the Keys of the Kingdom of Heaven to Peter, by Perugino

The Church is "one" because all her members are united in the one Faith, which they all profess.  We have the same sacrifice, which is the Mass, and the same Sacraments, and we are united under the same head of the Church, Jesus Christ, whose singular vicar on earth is the Supreme Pontiff, Pope Benedict XVI.  The Church is "one" because at her founding Jesus willed it to be so: "...that they all may be one..." (John 17:21).

Holy

The Church is holy because she was founded by Our Lord Jesus Christ, who is all-holy.  The Church continues in holiness because her teachings are those of Christ himself.  Those teachings, combined with the great Sacraments of the Church, are the means to leading a holy life and thus produce holy members in every age!

Now to the question at hand.... Catholic vs. Apostolic

"Catholic" comes from the Greek katholikos, which means "universal."  The Baltimore Catechism (still valid and still very much in need of being read by a great many Catholics) states that the Church is universal "because, destined to last for all time, it never fails to fulfill the divine commandment to teach all nations all the truths revealed by God."

"Apostolic," on the other hand, refers to the fact that the Church is founded upon the Apostles, who, following Our Lord's command to "teach all nations," spread the one true Faith to the ends of the earth.  According to Christ's Divine Will, His Apostles and their successors (the bishops) are the guardians and teachers of the Faith of the Church.  Insofar as the line of succession of the Sacraments and Doctrine of the Church may be traced back to the Apostles themselves--and in particular to St. Peter, the Prince of the Apostles, whose successor is the Vicar of Christ on earth, the "rock" on whom the Church would be built (cf. Mt. 16:18)--the Church is "Apostolic."

What is most important in all of this is to remember that ONLY those communities which bear the four marks may be considered to be "Churches" in the proper sense of the word.  All other religious factions and denominations are more appropriately called "ecclesial communities" because they lack one (if not all) of the fundamental, constitutive elements required to be considered a Church (see here for the Vatican's most recent explanation).