Amavasya

Amāvásyā or Amavasai (Tamil) means the lunar phase of the New moon in Sanskrit. Ancient Babylonian, Greek and Indian calendars used 30 lunar phases, called tithi in India. The dark moon tithi is when the Moon is within the 12 degrees of angular distance between the Sun and Moon before conjunction (syzygy). The New Moon tithi is the 12 angular degrees after syzygy. Amāvásyā is often translated as new moon since there is no standard term for the Moon before conjunction in English.