There are actually only four main moon phases, but each of those has a "half-way point" phase that can also be considered a distinct phase, making a total of eight phases if you count them all:

The Four Main Phases

1. New Moon: The moon is completely hidden from view as it's between the Earth and the Sun.

2. First Quarter: Half of the moon's face is illuminated, and it appears as a crescent on the right side.

3. Full Moon: The entire face of the moon is illuminated, appearing as a full circle.

4. Last Quarter: Half of the moon's face is illuminated, but this time it appears as a crescent on the left side.

The Four "Half-Way Point" Phases

1. Waxing Crescent: The moon is a thin crescent growing larger, appearing on the right.

2. Waxing Gibbous: The moon is more than half illuminated, growing fuller, appearing on the right.

3. Waning Gibbous: The moon is more than half illuminated, shrinking, appearing on the left.

4. Waning Crescent: The moon is a thin crescent shrinking, appearing on the left.

These eight phases are a result of the moon's orbit around the Earth and the changing angle of sunlight reflecting off its surface.