Full moon
Definition
A full moon is the lunar-cycle phase in which the Moon and the Sun sit one hundred and eighty degrees apart on the ecliptic, which corresponds to an exact opposition between the two bodies. The hemisphere of the Moon facing the Sun is fully lit from the angle of Earth. Astrology treats it as the climax of the monthly synodic cycle, the moment of peak symbolic visibility of the luminary pair and the midpoint of the arc opened at the new moon.
In context
If a full moon lands on the degrees of your Midheaven, the chart sketches a public visibility tied to that window of the calendar: a zone of the map where whatever the previous new moon planted becomes visible. The full moon inherits the geometry of every syzygy (the luminary pair aligned) but in the key of opposition rather than conjunction. Its sign tints the climax with an emotional color, and the house it falls in marks the sector of life where the lunation shows up with the most force of its own.
To go deeper
A full moon closes the major pair of lunar phases: