noun
Etymology: Middle English newe mone, newe moone, from Old English nīwe mōna
1.
a. : the moon's phase when it is in conjunction with the sun so that its dark side is turned toward the earth — see moon illustration
b. : the moon's dark appearance when at the new moon phase
c. : the position in the orbit when the moon is new
d. : the thin crescent moon seen in the western evening sky shortly after sunset for a few days after the actual occurrence of the new moon phase
2.
a. : the day when the new moon is first seen
b. : rosh hodesh