Yuga

noun Hinduism.

1. an age of time.
2. any of four ages, the Satya, the Treta, the Dvapara, and the Kali, each worse than the last, forming a cycle due to begin again when the Kali has come to an end.

noun

1. (in Hindu cosmology) one of the four ages of mankind, together lasting over 4 million years and marked by a progressive decline in the vitality and morals of men