Based on the literal
meaning of the word ("all the gods"), this name might be interpreted
as referring to all gods, or it can refer to a group of deities known as the
sons of Vishva, the celestial sage Daksha's daughter.
The number of sons varies across manuscripts and is either
10 or thirteen.
Although the Manu Smrti, one of the most important
scriptures in the dharma literature, requires daily gifts to the Vishvedevas,
they are especially venerated during memorial services for the deceased known
as shraddhas.
They are claimed to have received these daily offerings as a
reward for performing exceptionally severe asceticism.
You may also want to read more about Hinduism here.
Be sure to check out my writings on religion here.