When the moon is between the Sun and the Earth, the side of the moon facing the Earth is dark. This is called as “New Moon”. As the Moon travels eastwards, more of its sunlit side becomes visible to us and it is said to be waxing. This phase after the new moon is called “Waxing Crescent”. As the moon continues circling eastward, the Sun, the Earth, and the Moon, form a 90 degrees angle and the moon appears half-dark and half-light to us on the Earth. This is called as “ Waxing Gibbous “ phase.
As the moon continues its revolution around the Earth, the Sun, the Earth and the Moon align with the Earth in the middle. The side of the moon facing the Earth is fully lit. This is called as a “Full Moon”. As the moon travels further in its orbit, the lit portion visible to us becomes smaller and smaller. The moon is now said to be waning. Once again, the moon appears half dark and half light to us on the Earth. This is called as “Waning Gibbous” phase. As the moon completes its revolution around the Earth, the moon enters a “Waning Crescent” phase just before starting the cycle again as a new moon.