
In the Surya-Siddhanta, however, the former term is not once found, and the latter occurs only in these verses elsewhere, Age (yuga) alone is employed to denote it, and always denotes it, unless expressly limited by the name of the Golden (krta) Age. The period of 4,320,000 years is ordinarily styled Great Age (mahayuga), or, as above in two instances, Quadruple Age (caturyuga). Translation of the Surya-Siddhanta, A Text-Book of Hindu Astronomy With notes and an appendix. Sometimes, it is simply referred to as the process of creation and destruction (saṃhāravikṣepa MBh. Malinar, Angelika Narayanan, Vasudha (eds.). "Cosmic Cycles, Cosmology, and Cosmography". In other places 'yuga' must be given the sense of a 'long period of time'. Generally yuga appears to mean in the Rigveda 'generation' (lessening the life of human generations). In many places it appears to refer to a very brief period. The word yuga occurs at least thirty-eight times in the Rigveda, but the meaning is rather doubtful.

Journal of the Bombay Branch of the Royal Asiatic Society. "Kalivarjya (actions forbidden in the Kali Age)". It is quite clear that the smallest unit was the 'nimisah', and that time in the general sense of past, present and future was indicated by the word 'yuga'.

The names " Yuga" and "Age" commonly denote a catur-yuga (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.

In the Mahabharata, the words yuga and kalpa (a day of Brahma) are used interchangeably to describe the cycle of creation and destruction. In the Rigveda, a yuga refers to generations, a long period, a very brief period, or a yoke (joining of two things). A yuga, in Hinduism, is generally used to indicate an age of time.
