What is the Season of Advent?
Advent is the start of the Liturgical Year in Catholicism, and a tradition which has been maintained in many other Christian cultures. The Liturgical Year ends on the "Last Sunday After Pentecost" or also called the "Last Sunday in Ordinal Time" (ordinal means "counting" - since we count the weeks after Pentecost - there is also an ordinal time after Epiphany, prior to the observance of Lent). The celebration on this last Sunday of the year is in honor of Christ the King. Then comes the "Catholic New Year!" This is the time of Advent, a time of anticipation and preparation for the celebration of the birth of our Lord and Savior, Jesus Christ. We are reminded of the Scripture "Prepare ye the way of the Lord" (I always recollect the Godspell tune of the same name). Advent takes place on the four Sundays prior to the celebration of the Christ Mass (Christmas), which is celebrated on December 25th each year. Since Advent is tied to the Sundays prior to the Christ Mass and that Mass can be on any day of the week being tied to the calendar date of December 25th, the beginning of and length of Advent varies from year to year. Advent ends traditionally at the Midnight Mass of December 25th (though in many/most modern traditions this Mass is now a "vigil Mass" on the evening of December 24th - more on that in a bit).
We celebrate the time of Advent as a time of anticipation and preparation/penance for the coming of the Lord. The season is just prior to the Christ Mass Season - which celebrates His First Coming, but the Scripture readings for Advent deal mostly with His Second Coming. Thus the Advent Season is really a time of reflection of our lives preparing the way of the Lord to come again. whether it be in our lifetime or sometime in the future. The key point would be to be ready for Him, for no man knoweth the hour. So, while we sing Vene, Vene (O Come, O Come) Emmanuel - while not losing sight of the upcoming Christ Mass, let us also join in calling for His Second Coming!