8 phases of the moon
Four additional terms help define the phases in-between. The first two refer to the illumination of the Moon. The term waxing is used when the Moon is becoming more illuminated as it goes from new to full Moon. Opposite of that is the term waning, which is used when the Moon goes from full to new and becomes less illuminated every night. So, as the Moon “grows,” it is waxing, and as it “shrinks” it is waning. The two other terms refer to the shape of the Moon. Crescent refers to the phases where the moon is less then half illuminated. When the Moon is more then half full, it is considered gibbous.
Thus you can simply combine the four terms to create the last four phase names. After the new Moon, the illuminated portion of the Moon is increasing, but is less than half full. As a result, the intermediate stage between new Moon and first quarter is called a waxing crescent. After the first quarter, the sunlit portion is still increasing, but now it is more than half full, so it is a waxing gibbous. After the full Moon, the illumination switches and begins to decrease. So the waning gibbous phase occurs next. Following the third quarter is the waning crescent, which wanes until the light is completely gone, bringing us full circle to a new Moon.
Together, this brings the Moon through 8 named phases as it goes through one lunar phase cycle, new Moon, waxing crescent, first quarter, waxing gibbous, full Moon, waning gibbous, third quarter, and finally waning crescent.