Beginning the Church's liturgical year, Advent (from, "ad-venire" in Latin or "to come to") is the season encompassing the four Sundays (and weekdays) leading up to the celebration of Christmas.
The Advent season is a time of preparation that directs our hearts and minds to Christ’s second coming at the end of time and to the anniversary of Our Lord’s birth on Christmas. From the earliest days of the Church, people have been fascinated by Jesus’ promise to come back. But the scripture readings during Advent tell us not to waste our time with predictions. Advent is not about speculation. Our Advent readings call us to be alert and ready, not weighted down and distracted by the cares of this world (Lk 21:34-36). Like Lent, the liturgical color for Advent is purple since both are seasons that prepare us for great feast days. Advent also includes an element of penance in the sense of preparing, quieting, and disciplining our hearts for the full joy of Christmas.
(information taken from https://www.usccb.org/prayer-worship/liturgical-year/advent)
"Advent, this powerful liturgical season that we are beginning, invites us to pause in silence to understand a presence. It is an invitation to understand that the individual events of the day are hints that God is giving us, signs of the attention he has for each one of us."
~ Pope Benedict VXI, Homily at First Vespers of Advent, November 28, 2009