The Hindu scriptures posit mokṣa or liberation from transmigratory existence as the ultimate goal of life. According to some Vedāntic works, this is attained when the jīva or the individual soul gets merged in Brahman or Paramātman, the Absolute or the Supreme Soul.
Nirvāṇa means getting extinguished like a burning lamp being blown out. When the little or the individual self (jīvātman) extinguishes itself into Brahman the Absolute, losing its separate identity and becoming merged in Brahman, it is brahmanirvāṅa. Another example that expresses the same idea is the merging of the rivers into the ocean.
Brahmanirvāṇa or mokṣa can be attained through jñāna (knowledge) and bhakti (devotion).
This word seems to be peculiar only to the Bhagavadgītā (vide 2.72; 5.24-26).