Liturgical Calendar
The liturgical calendar, also called the liturgical year, church year, Christian year, ecclesiastical calendar, or kalendar, is the cycle of liturgical days and seasons that determines when feast days, including celebration and commemoration of particular saints, or events in the life of Jesus and the Church are to be celebrated. There is a variety in calendars, particularly between Eastern and Western Calendars which are traditionally based off of the Julian and Gregorian Calendars respectively. Other dates such as Easter are "movable feasts" which vary, not only between different traditions which have different reckoning systems for deriving the date of Easter, but vary from year to year based on a lunar calendar.
Liturgical Cycle
Liturgical Colors
Distinct liturgical colors are often used during different seasons of the liturgical year, dictating the color of vestments and other church decorations and ornaments.
Ordinary Time
The corresponding liturgical color of Ordinary Time is green. As the name suggests, Ordinary Time is any time when no other season is being celebrated and occurs twice; after Pentecost/Whitsunday and before Advent, and after Epiphany, and before Lent.
The Book of Common Prayer
The various Books of Common Prayer have slight variety in their liturgical calendar, but generally follow the format of:
Advent -> Christmastide -> Epiphany -> Ordinary Time -> Lent -> Eastertide -> Whitsunday -> Ordinary Time
During the Liturgical Movement in the 20th Century, there was an ecumenical effort to unify the liturgical calendars of various communions, and in order to better align the Anglican Calendar with the Lutheran, Methodist, Roman Catholic, and other Western communions. For this reason the 1979 Prayerbook and the 2019 Prayerbook are more closely aligned with the Post-Vatican II Roman Rite, and use more ecumenical terms like "Pentecost" for Whitsunday.