Nirvana

Both the Pali word Nibbàna [the verb is ni(r) and nibbati] and the Sanskrit Nirvàna [the verb is nir-va] refer to the state of extinction, or cessation , calmness, disappearance, liberation, peacefulness, and perfect wisdom.   At this level, there is no birth nor death.  Nirvana is the ultimate goal  for Buddhists.  That is why Nirvana is one of the three Dharma signs in Buddhism: Nirvana, Peace, and Tranquility.

Nirvana has four states.  First, Buddha Nature, which is the eternal state of Suchness, pure and bright, and unchanged.  Second, the final state in a Buddhist's life-long practice when all the five skandas and all sufferings and fetters have come to a cessation (as in the case of the Buddha's demise).  Third, the highest spiritual level which a Buddhist may attain.  At this level the practitioner is still alive, but is completely free from any suffering caused by greed, hatred, and ignorance, and by the preconceived existence of a "self," and has attained liberation and perfect wisdom.  And fourth, a state of no boundaries: Nirvana is free from any fetters set by birth-death, by attachment/desire-hatred, by discriminative preconceptions, or by dualistic notions and concepts.  Nirvana has no form, and no language can describe or express it.

Four key characteristics of Nirvana are: Permanence, Supreme Happiness, No Form/Self (hence, it is Reality or Ultimate Truth), and Supreme Peace/Tranquility.