D defs.my
Entry 1 sense Webster, 1913

Lunation

· Lu·na·tion · IPA /luːˈneɪʃən/
01 n. The period of a synodic revolution of the moon, or the time from one new moon to the next; varying in length, at different times, from abou…
  1. 1.
    The period of a synodic revolution of the moon, or the time from one new moon to the next; varying in length, at different times, from about 29<frac:1_4/ to 29<frac:5_6/ days, the average length being 29 d., 12h., 44m., 2.9s.