What is the antonym of full moon day?

Answer 1

In astronomical terminology, the New Moon is the lunar phase that occurs when the Moon, in its monthly orbital motion around Earth, lies between Earth and the Sun, and is therefore in conjunction with the Sun as seen from Earth. At this time, the illuminated half of the Moon faces directly toward the Sun, and the dark or unilluminated portion of the Moon faces directly toward Earth, so that the Moon is invisible as seen from Earth. [Note: The illuminated half of the moon always faces directly toward the sun, as does the illuminated half of any body orbiting the sun. It's the moon's position relative to both the sun and earth that matters.]

Answer 2

The opposite of a full moon is a new moon.

Answer 3

Waxing.

http://en.wikipedia.org/wiki/File:Lunar-Phase-Diagram.png