Lunar phase or phases of moon indicates the illuminated portion of the moon that we can observes from the earth.
The revolution of moon around earth makes it appear like it is changing shapes.The phase or the shape of the moon depends upon its position in relation to the Sun and the Earth.
The phases are named on the basis of how much moon we can see and whether moon size is increasing or decreasing.The phases of moon start in a cycle which starts from new moon.On new moon day, moon is not visible.From here it goes on increasing size and becomes full moon. Increasing phase is known as waxing moon.
Once it takes the full moon position, then the size starts deceasing, this part is known as waning.