The liturgical year, also known as the Christian year, consists of the cycle of liturgical seasons which determines when Feasts, Memorials, Commemorations, and Solemnities are to be observed and which portions of Scripture are to be read.

The cycle of the year defines a series of seasons, which are associated with different ways of decorating churches, different vestments for clergy, and different topics for reading from the Bible and preaching. These, especially the recommended bible passages for each Sunday, are recorded in lectionaries. The Sundays are denoted as "the first Sunday in Advent", "the twenty-third Sunday after Pentecost", etc.

Because of the dominance of Christianity in Europe throughout the Middle Ages, many features of the Christian year became incorporated into the secular calendar. Many of its feasts remain holidays, and are now celebrated by people of all faiths and none - in some cases worldwide. The celebrations bear varying degrees of relationship to the religious feasts from which they derived, often also including elements of ritual from pagan festivals of similar date.

Generally, the liturgical seasons are Advent, Christmas, Time after Epiphany, Lent, Easter, and Time After Pentecost.

Advent
First season of the liturgical year. It is traditionally a fast, and begins four Sundays before Christmas and ends on Christmas Eve. Its purpose is the preparation for Christmas, with the focus on expectation.

Christmas
Typically begins with a worship service or a Vigil Mass on Christmas Eve (December 24) and ends on the Feast of the Baptism of the Lord on the Sunday after January 6 (formerly on the eighth and final day of the Octave of Epiphany, or January 13). Christmas Day itself is December 25.

Ordinary Time
Ordinary comes from the same root as our word ordinal, and in this sense means "the counted weeks." These are the common weeks which do not belong to a proper season. It consists of either 33 or 34 Sundays, depending on the year. The first part (formerly known as the season after Epiphany) extends from the Monday following the Christmas Season (or, in the United States only, from the Tuesday in years when the first Sunday after January 6 falls on January 7 or 8, in which case the Feast of the Baptism of the Lord is observed on a Monday instead of a Sunday) through the Tuesday before Ash Wednesday, the beginning of Lent. This first installment of Ordinary Time has anywhere from four to nine Sundays, depending on how early or late Easter falls in a given year.

Lent
Lent is a major fast taken by the Church to prepare for Easter. It begins on Ash Wednesday and ends on Holy Thursday, in Holy Week. There are forty days of Lent, counting from Ash Wednesday through the Easter Triduum, but not including Sundays. The last two weeks of Lent are known as "Passiontide," which begins on Passion Sunday; the final week of Lent is known as "Holy Week," which begins on Palm Sunday. The final three days of Lent are known as the Easter Triduum.

Easter
The date of Easter varies from year to year, but is set to be close to the date of Jesus' resurrection, which the holiday recognizes. The Easter season extends from the Easter Vigil through Pentecost Sunday.