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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...

era

(Encyclopedia)era, period of historic time. In geology, it is the name applied to large divisions of geological process, e.g., Paleozoic era (see geology). In chronology an era is a period reckoned from a fixed poi...

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...

week

(Encyclopedia)week, period of time shorter than the month, commonly seven days. The ancient Egyptians used a 10-day period, as did the French under the short-lived French Revolutionary calendar. In many regions a f...

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 ...

Palm Sunday

(Encyclopedia)Palm Sunday, in the Christian calendar, the Sunday before Easter, sixth and last Sunday in Lent, and the first day of Holy Week. It recalls the entry of Jesus into Jerusalem riding upon an ass, when h...

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...

year

(Encyclopedia)year, time required for the earth to complete one orbit about the sun. The solar or tropical year is measured relative to the sun and is equal to 365 days, 5 hr, 48 min, 46 sec of mean solar time (see...

Whitby, Synod of

(Encyclopedia)Whitby, Synod of, called by King Oswy of Northumbria in 663 at Whitby, England. Its purpose was to choose between the usages of the Celtic and Roman churches, primarily in the matter of reckoning the ...
 

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