Kalpa. In Hinduism, a day and a night in the life of Brahmā, consisting of four yugas, i.e. one mahā (great) yuga; or sometimes calculated as 1,000 yugas; in any case, an immense endurance of time.

In Buddhism (Pāli, kappa), the length of a kalpa is equally vast: through the four stages of a kalpa, a universe arises, continues, declines, persists in chaos. Within this mahākalpa, there are twenty small kalpas.

kalpa in Hindu and Buddhist tradition, an immense period of time, reckoned as 4,320 million human years, and considered to be the length of a single cycle of the cosmos (or ‘day of Brahma’) from creation to dissolution.