Amavas or Amavasya, (Massia in Punjabi), literally a combination of ama (together) and vasya (stationing), signifying the coming of the sun and the moon together in one line. It is the last day of the dark half of the lunar month when the moon remains entirely hidden from our view.
The twenty eight naksatras (phases), considered to be the wives of the moon, are the lunar mansions or stations through which the moon passes as does the sun through the twelve signs of the zodiac.
In some cultures, the life of an individual is believed to be deeply influenced by the naksatra through which the moon passed at the time of his birth. Thus, different days such as panchami (fifth), ekadasi (eleventh), puranmashi (the fifteenth day when the moon is full) and amavas assumed a special significance in the Hindu tradition. Certain religious performances and observances came to be associated with these days.
In Sikh Scripture, the Guru Granth Sahib, occur three compositions under the title Thiti or Thitm with couplets to match the lunar days. The burden of these compositions is that no single day is more auspicious than the others. That day alone is auspicious and well spent which is spent in meditating on the Divine Name and in doing good deeds. Although there is no ritualistic or formal observance prescribed in Sikh system for Amavas, the day is marked by special congregations in gurdwaras.