The liturgical year, also known as the church year or Christian year, as well as the kalendar, consists of the cycle of liturgical seasons in Christian churches that determines when feast days, including celebrations of saints, are to be observed, and which portions of Scripture are to be read either in an annual cycle or in a cycle of several years.
Distinct liturgical colours may appear in connection with different seasons of the liturgical year. The dates of the festivals vary somewhat between the different churches, though the sequence and logic is largely the same.
The liturgical cycle divides the year into a series of seasons, each with their own mood, theological emphases, and modes of prayer, which can be signified by different ways of decorating churches, colours of paraments and vestments for clergy, scriptural readings, themes for preaching and even different traditions and practices often observed personally or in the home. In churches that follow the liturgical year, the scripture passages for each Sunday (and even each day of the year in some traditions) are specified in a lectionary.
A calendar (sometimes historically spelled kalendar) is, in the context of archival science and archival publication, a descriptive list of documents. The verb to calendar means to compile or edit such a list. The word is used differently in Britain and North America with regard to the amount of detail expected: in Britain, it implies a detailed summary which can be used as a substitute for the full text; whereas in North America it implies a more basic inventory.
The term derives from a (now somewhat archaic) word meaning a list or register of any kind. Although the documents in a calendar are generally arranged in chronological order, the term has only an indirect relationship to a table of dates.
In the British tradition, the word normally implies a full descriptive summary (often published) in which each document is the subject of a "carefully controlled, rigorously consistent précis". All significant elements in the text are recorded, so that the great majority of researchers will be spared the need to consult the originals: the completed calendar effectively becomes a substitute for the archival documents, and is often treated as a primary source in its own right. Trivial or incidental elements ("common form and unnecessary verbiage") are omitted; but all names, dates and significant statements are noted, and passages which appear to the editor to be of particular interest or importance may be quoted in full. Documents in archaic or foreign languages (particularly Latin) are normally calendared in the modern vernacular, but significant or ambiguous terms or passages may be given in the original language. A calendar is therefore less detailed or comprehensive than a series of full transcripts or translations; but considerably more detailed than an archival list or other finding aid.