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month
(Encyclopedia)month, in chronology, the conventional period of a lunation, i.e., passage of the moon through all its phases. It is usually computed at approximately 29 or 30 days. For the computation of the month a...tropical year
(Encyclopedia)tropical year, time between successive vernal equinoxes; 365 days, 5 hr, 48 min, 46 sec of mean solar time (see solar time). The tropical year is the basis of the year used in the Gregorian calendar. ...New Year's Day
(Encyclopedia)New Year's Day, among ancient peoples the first day of the year frequently corresponded to the vernal or autumnal equinox, or to the summer or winter solstice. In the Middle Ages it was celebrated amo...Rogation Days
(Encyclopedia)Rogation Days, in the calendar of the Western Church, four days traditionally set apart for solemn processions to invoke God's mercy. They are Apr. 25, the Major Rogation, coinciding with St. Mark's D...synodic period
(Encyclopedia)synodic period sĭnŏdˈĭk [key], in astronomy, length of time during which a body in the solar system makes one orbit of the sun relative to the earth, i.e., returns to the same elongation. Because ...Gregory XIII
(Encyclopedia)Gregory XIII, 1502–85, pope (1572–85), an Italian named Ugo Buoncompagni, b. Bologna; successor of St. Pius V. He is best known for his work on the calendar, and the reformed calendar, the Gregori...liturgy, Islamic
(Encyclopedia)liturgy, Islamic, mandatory ritual prayer in Islam (salat) is performed five times a day at dawn, noon, afternoon, sunset, and night. It requires ritual cleanliness, and is preceded by ablutions. The ...Islamic State
(Encyclopedia)Islamic State (IS), Sunni Islamic militant group committed to the establishment of an Islamic caliphate that would unite Muslims in a transnational, strict-fundamentalist Islamic state. IS has been ma...Easter
(Encyclopedia)Easter [A.S. Eastre, name of a spring goddess], chief Christian feast, commemorating the resurrection of Jesus after his crucifixion. In the West, Easter is celebrated on the Sunday following the full...Organization of the Islamic Conference
(Encyclopedia)Organization of the Islamic Conference: see Organization of Islamic Cooperation. ...Browse by Subject
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