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, Table IV., look for April, and the epact 28 is found opposite the second day.

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

Thus, when the epact is 17, the new and full moons of March fall on the 13th and 28th.

From A Budget of Paradoxes, Volume I by Smith, David Eugene

Subtract the epact from 57, divide by 7, and keep the remainder, or 7, if there be no remainder.

From A Budget of Paradoxes, Volume I by Smith, David Eugene

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

On account of the solar equation S, the epact J must be diminished by unity every centesimal year, excepting always the fourth.

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