Yuga

A yuga, in Hinduism, is generally used to indicate an age of time.

In the Rigveda, a yuga refers to generations, a period of time (whether long or short), or a yoke (joining of two things). In the Mahabharata, the words yuga and kalpa (a day of Brahma) are used interchangeably to describe the cycle of creation and destruction.

In post-Vedic texts, the words "yuga" and "age" commonly denote a (pronounced chatur yuga), a cycle of four world ages—for example, in the Surya Siddhanta and Bhagavad Gita (part of the Mahabharata)—unless expressly limited by the name of one of its minor ages: Krita (Satya) Yuga, Treta Yuga, Dvapara Yuga, or Kali Yuga.

The term "yuga" can represent the number 4. In early Indian astronomy, it referred to a five-year cycle starting with the conjunction of the sun and moon in the autumnal equinox.