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.
Etymology
Yuga () means "a yoke" (joining of two things), "generations", or "a period of time" such as an age, where its archaic spelling is yug, with other forms of yugam, , and yuge, derived from yuj (), believed derived from (Proto-Indo-European: 'to join or unite').
In the Latin language, juga or jug is used from the word jugum, which means "a yoke used to connect two oxen" (e.g. cali-juga = kali-yuga).
See also
Hindu units of time
Kalpa (day of Brahma) Manvantara (age of Manu) Pralaya (period of dissolution) Yuga Cycle (four yuga ages): Satya (Krita), Treta, Dvapara, and Kali List of numbers in Hindu scriptures