Kalpa

Kalpa is a Sanskrit word ((devanāgarī: कल्प) meaning a relatively long period of time (by human calculation) in Hindu and Buddhist cosmology. The concept is first mentioned in the Mahabharata. The definition of a kalpa equalling 4.32 billion years is found in the Puranas (specifically Vishnu Purana and Bhagavata Purana).

A kalpa is a day of Brahmā, and consists of a thousand cycles of four yugas or ages.

Maha-Kalpa

Brahmā’s months are said to be 30 of his days long and his year is 12 of his months; his lifetime is said to be 100 of his years

The Maha-Kalpa embraces the whole lifetime of Brahmā, which is of 100 years (1 year are 12 of his months, which consist of 30 days each).

In The Secret Doctrine the Maha-Kalpa is referred to as the "seven eternities:"

The Seven Eternities meant are the seven periods, or a period answering in its duration to the seven periods, of a Manvantara, and extending throughout a Maha-Kalpa or the “Great Age”—100 years of Brahmâ—making a total of 311,040,000,000,000 of years; each year of Brahmâ being composed of 360 “days,” and of the same number of “nights” of Brahmâ (reckoning by the Chandrayana or lunar year); and a “Day of Brahmâ” consisting of 4,320,000,000 of mortal years.

Further reading

• Kalpa at Theosopedia