new moon

Short definition from Wiktionary

Noun

1. 1
   The phase of the moon when it is in conjunction with the sun and is therefore obscured.
2. 2
   The moon when it is in conjunction with the sun.
3. 3
   The phase of the moon when it is waxing.
4. 4
   The moon when it is waxing.
5. 5
   The day when the new moon is first seen or is expected to appear.