This is the Moon of Rest and Release.

The Dark moon is the period when the Moon appears so close to the Sun in the sky that it cannot be seen even near sunset or sunrise. Depending on how close the Moon passes to the line between Earth and Sun, dark moon may last between 1.5 to 3.5 days. The astronomical new moon occurs in the middle of this period when the Moon and Sun are in conjunction, and is also referred to as dark moon to distinguish it from the traditional new moon, which is the moment when the crescent moon is first seen one or two days after conjunction.

It is the time of the Crone Goddess. She who is known by the names Hecate, Nuit, Banba, Erda, Macha, MotherNight, Sekhmet, the Morrigu and many, many more. The most silent and all-encompassing Crone, Our  Lady of the DarkMoon.

The Dark Moon is a very comtemplative and inner-vision time.

Major workings of the Dark Moon include protective magick, healing, releasing and banishing.

An easy way to recall waxing or waning:

The waxing Moon takes the place of a "D" , it is developing to its fullness. The waning Moon is "C", which is condensing and contracting or getting smaller.