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 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.