Some schools of Buddhism explain Nirvana as a state of bliss or peace, and this state may be experienced in life, or it may be entered into at death.
The word Nirvana means "to extinguish," such as extinguishing the flame of a candle. This "extinguishment" is not understood by Buddhists to mean annihilation. Rather, it is thought of as passing into another kind of existence.
In early forms of Buddhism, Nirvana was understood to be liberation from the cycle of death and rebirth and freedom from the effects of karma. Later, in Mahayana Buddhism, Nirvana came to be thought of as oneness with the Absolute. However, the Absolute is the union of Nirvana and Samsara.
The various schools of Buddhism have diverse teachings about whether Nirvana can be attained before death or only after death.
