epact

American  

[ee-pakt] / ˈi pækt /

noun

1. the difference in days between a solar year and a lunar year.

2. the number of days since the new moon at the beginning of the calendar year, January 1.

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epact British  

/ ˈiːpækt /

noun

1. the difference in time, about 11 days, between the solar year and the lunar year

2. the number of days between the beginning of the calendar year and the new moon immediately preceding this

3. the difference in time between the calendar month and the synodic month

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Etymology

Origin of epact

1545–55; < Late Latin epacta < Greek epaktḗ, noun use of feminine of epaktós added, equivalent to ep- ep- + ag ( ein ) to lead + -tos verbid suffix

Example Sentences

In the calendar this epact first occurs before the 2nd of December at the 26th of November.

From Encyclopaedia Britannica, 11th Edition, Volume 4, Part 4 "Bulgaria" to "Calgary" by Various

It should be borne in mind that the epacts are obtained by successively adding eleven to the epact of the former year, and rejecting thirty as often as the sum exceeds or equals that number.

From Our Calendar by Packer, George Nichols

The third column corresponding to the golden number 3, has for its first epact 12 + 11 = 23; and in the same manner all the nineteen columns of the table are formed.

From Encyclopaedia Britannica, 11th Edition, Volume 4, Part 4 "Bulgaria" to "Calgary" by Various

In using the calendar, if the epact of the year is 25, and the golden number not above 11, take 25; but if the golden number exceeds 11, take 25′.

From Encyclopaedia Britannica, 11th Edition, Volume 4, Part 4 "Bulgaria" to "Calgary" by Various

There only needs to add together the epact, number of the month, and day of the month; the sum of which, if under thirty, gives the moon's age--the excess, if over.

From The History of Sumatra Containing An Account Of The Government, Laws, Customs And Manners Of The Native Inhabitants by Marsden, William