menstrual epact

1 definition found

menstrual epact - Collaborative International Dictionary of English v.0.48 :

  Epact \E"pact\ ([=e]"p[a^]kt), n. [F. ['e]pacte, fr. Gr.
     'epakto`s brought on or in, added, fr. 'epa`gein to bring on
     or in; 'epi` on, in + 'a`gein to bring or lead. See Epi-,
     and Act.] (Chron.)
     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.
     [1913 Webster]
  
     Annual epact, the excess of the solar year over the lunar
        year, -- being eleven days.
  
     Menstrual epact, or Monthly epact, the excess of a
        calendar month over a lunar.
        [1913 Webster]