A lunar cycle has 4 quarters. The full moon is the 3rd quarter (the new moon is the 1st). Astrologically, a full moon is when the sun and moon are in exact opposition within the zodiac.
 

Astrological Charts, Blogging and Social Networking.

"A reader asked me what it meant that the recent New Moon in Libra fell conjunct their Pluto. That got me to thinking, and you know what that means....
While forming the answer to the query, I realized that at certain points in the year, a series of New Moons and Full Moons in fact do stimulate many of the "generational planets" in our charts. Whether Uranus, Neptune, or Pluto, there are a sequence of Lunations that trigger these outer, invisible, "transpersonal" energies, allowing us to face spiritual lessons that evolve us in major ways."