Gregorian calendar


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Related to Gregorian calendar: lunar calendar, Julian calendar

Gregorian calendar

(grĕ-gor -ee-an, -goh -ree-) The calendar that is now in use throughout most of the world and that was instituted in 1582 by Pope Gregory XIII as the revised version of the Julian calendar. The simple Julian four-year rule for leap years was modified so that when considering century years only one out of four, i.e. only those divisible by 400, were to be leap years: 1700, 1800, and 1900 were not leap years. There are therefore 365.2425 days per year averaged over 400 years. This greatly reduced the discrepancy between the year of 365.25 days used in the Julian calendar and the 365.2422 days of the tropical year, which had resulted in the accumulation of 14 days over the centuries.

The revision came into effect in Roman Catholic countries in 1582, the year being brought back into accord with the seasons by eliminating 10 days from October: Thursday Oct. 4 was followed by Friday Oct. 15. The vernal equinox, which would have occurred on Mar. 11 and which had originally fallen on Mar. 25 in Julius Caesar's time was thus adjusted to Mar. 21. Gregory also stipulated that the New Year should begin on Jan. 1. Non-Catholic countries were slow to accept the advantages of the Gregorian reform. Britain and its colonies switched in 1752 when an additional day had accumulated between old and new calendars: Sept. 2, 1752 was followed by Sept. 14 and New Year's Day was changed from Mar. 25 to Jan. 1, beginning with the year 1752. The very slight discrepancy between the Gregorian year and the tropical year amounts to about three days in 10 000 years.

Gregorian Calendar

 

(New Style), the calendar system that replaced the insufficiently accurate Julian calendar (Old Style). In contrast to the latter, the Gregorian calendar specified that century years were to be leap years only if they were evenly divisible by 400. The Gregorian calendar was first adopted by a number of European countries in 1582. The USSR adopted it in February 1918.

Gregorian calendar

[grə′gȯr·ē·ən ′kal·ən·dər]
(astronomy)
The calendar used for civil purposes throughout the world, replacing the Julian calendar and closely adjusted to the tropical year.

Gregorian calendar

(time)
The system of dates used by most of the world. The Gregorian calendar was proposed by the Calabrian doctor Aloysius Lilius and was decreed by, and named after, Pope Gregory XIII on 1582-02-24. It corrected the Julian calendar whose years were slightly longer than the solar year. It also replaced the lunar calendar which was also out of time with the seasons. The correction was achieved by skipping several days as a one-off resynchronisation and then dropping three leap days every 400 hundred years. In the revised system, leap years are all years divisible by 4 but excluding those divisible by 100 but including those divisible by 400. This gives a mean calendar year of 365.2425 days = 52.1775 weeks = 8,765.82 hours = 525,949.2 minutes = 31,556,952 seconds. leap seconds are occasionally added to this to correct for irregularities in the Earth's rotation.
References in periodicals archive ?
The Gregorian calendar says that Easter can fall anytime between March 22 and April 25, while according to Julian calendar, Easter can be celebrated anytime between April 4 and May 8.
Time passed smoothly and accurately until 1800, which was not a leap year in the new Gregorian calendar but would have been in the old Julian system.
Pakistan is an Islamic country and also follows the Islamic calendar in addition to the Gregorian calendar.
BEIRUT: Former Prime Minister Sd Hariri expressed his best wishes to the Lebanese Monday, particularly the country's Christians, on the occasion of Easter for the Christian communities that follow the Gregorian calendar.
The Gregorian calendar has a simple rule to take care of that.
However, the Gregorian calendar has only 365 days in a year, so if we didn't add a day on February 29 every four years, we would lose almost six hours every year.
Hanukkah is observed for eight nights and days, starting on the 25th day of Kislev according to the Hebrew calendar, which may occur at any time from late November to late December in the Gregorian calendar.
Ethiopia is unique in that it follows the Julian calendar, which is eight years behind the Gregorian calendar adopted my most of the world.
In the late 16th century, the Gregorian calendar was adopted as the international civil calendar.
Because it follows the lunar cycle, Ramadan comes 11 days earlier every year on the Gregorian calendar, bringing the fasting month this year in the summer.
Even today, despite adopting the Gregorian calendar, the Chinese still turn to their traditional lunar calendar to mark New Year (second full moon after the winter solstice), along with a panoply of assorted holidays and festivals.
This study will explore the introduction of the Gregorian calendar in 1582, the rejection of this calendar by sixteenth-century Protestants, and its eventual modification and acceptance by eighteenth-century Geneva.