from The American Heritage® Dictionary of the English Language, 4th Edition
- n. The period of time necessary to bring the solar calendar into harmony with the lunar calendar.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. the time (number of days) by which a solar year exceeds twelve lunar months; it is used in the calculation of the date of Easter
from the GNU version of the Collaborative International Dictionary of English
- n. The moon's age at the beginning of the calendar year, or the number of days by which the last new moon has preceded the beginning of the year.
from The Century Dictionary and Cyclopedia
- n. The excess of a solar over a lunar year or month. Hence, usually A number attached to a year by a rule of the calendar to show the age, in days completed and commenced, of the calendar moon at the beginning of the year—that is, on January 1st in the Gregorian, Victorian, and early Latin calendars, or March 22d in the Dionysian calendar, or old style.
French épacte, from Late Latin epacta, from Greek epaktē (hēmera), intercalary (day), feminine of epaktos, brought in, inserted, from epagein, to bring in, introduce : ep-, epi-, epi- + agein, to lead; see ag- in Indo-European roots.(American Heritage® Dictionary of the English Language, Fourth Edition)