The Waxing Gibbous, Approaching Fullness

The Waxing Gibbous is the phase between the first quarter and the full moon, when more than half the disc is lit and the illumination continues to increase toward complete. The word gibbous describes the swollen, more-than-half shape. The waxing gibbous Moon rises in the afternoon and is prominent through the evening and much of the night. Traditionally it is read as a phase of refinement and near-completion, the last growth and adjustment before fullness. These are the astronomical facts of the phase together with the meanings traditions attach to it; the shape is simply the sunlit hemisphere of the Moon seen from an angle that reveals most but not yet all of it, as the Moon moves toward the point in its orbit opposite the Sun where the full moon occurs.

Because the Moon's orbit is not a perfect circle, its distance from Earth varies over the course of a month, and a waxing gibbous Moon near perigee, its closest approach, can appear measurably larger and brighter than one near apogee at the same fraction of illumination, an effect popularly called a supermoon when it coincides with the full moon two phases later. The gibbous shape itself, from the Latin gibbus for hump, was a term astronomers had long used for other partially lit bodies before it settled into its modern near-exclusive association with this lunar phase. Traditionally the waxing gibbous is treated as a phase of trust rather than of doubt, the outcome no longer in question but the details still being refined before the fullness two or three nights ahead.