The dark moon is the time when the Moon is 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, this may be anywhere from 1.5 to 3.5 days long. The astronomical new moon is the moment in the middle of this period when the Moon and Sun are in conjunction. The term dark moon is used as a name for this moment as well, to distinguish it from the moment when the crescent new moon is first seen, which was the original meaning of the term "new moon" and is the next phase after dark moon.
see also:
syzygy, new moon
"Dark Moon" is the name of a 1957 hit song with recordings done by both traditional pop music singer Gale Storm and country music artist Bonnie Guitar . "Dark Side of the Moon" is the name of a well-known Pink Floyd album.