The name joins dhan (wealth) with teras (the thirteenth day). The day is about welcoming prosperity into the home before the main Diwali night, which is why so many families buy something new, often a metal utensil, a coin or a piece of jewellery, and offer it in the evening puja before using it.
Dhanteras is also Dhanvantari Jayanti, the day Dhanvantari is said to have emerged from the churning of the ocean holding a pot of nectar (amrit). He is the patron of Ayurveda, and the day is a reminder that good health is the first wealth. The Government of India observes this day as National Ayurveda Day.
In the evening, a lamp is lit for Yama outside the main door, facing south. This Yama Deepam (Yama Deepdaan) is a quiet prayer for the long life and safety of the family, offered with gratitude rather than fear.
During the churning of the cosmic ocean (Samudra Manthan) by the gods and the asuras, many treasures rose from the waters. Among the last to appear was Dhanvantari, carrying the pot of amrit, the nectar of immortality. Because he brought healing and long life to the world, he is remembered on this day as the physician of the gods.
A well-known folk story explains the Yama Deepam. A king named Hima was told that his son would die on the fourth night after his marriage. On that night, the young bride kept him awake, piled her gold and silver ornaments at the door of their room, lit many lamps and told stories and sang songs. When Yama arrived in the form of a serpent, he was dazzled by the light and the glitter, sat listening to the songs, and left at dawn without taking the prince. Since then, families light a lamp for Yama on this evening as a prayer for the protection of their loved ones.
