lunation
nounThe time that elapses between successive new moons, averaging 29 days, 12 hours, 44 minutes; a lunar month.
nounThe period of a synodic revolution of the moon, or the time from one new moon to the next.
nounThe 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 291/4 to 295/6 days, the average length being 29 d., 12h., 44m., 2.9s.
nouna month of approximately 29.53
The
the period between successive new moons (29.531 days)