Webster's Dictionary 
(n.) In the Buddhist system of religion, the final emancipation of the soul from transmigration, and consequently a beatific enfrachisement from the evils of wordly existence, as by annihilation or absorption into the divine. See Buddhism.
Cyclopedia of Biblical, Theological and Ecclesiastical Literature 
(from the Sanscrit nir," out," and vana, "blown;" hence, literally, that which is blown out or extinguished) is, in Buddhistic doctrine, the term denoting the final deliverance of the soul from transmigration. It implies, consequently, the last aim of Buddhistic existence, since transmigration is tantamount to a relapse into the evils or miseries of Sansara, or the world. But as Hind Û ism, or the Brahmanical doctrine, professes to lead to the same end, the difference between Nirvana and Moksha, Apavarga, or the other terms of Brahmaism designating eternal bliss, and consequent liberation from metempsychosis, rests on the difference of the ideas which both doctrines connect with the condition of the soul after that liberation. Brahman, according to the Brahmanical doctrine, being the existing and everlasting cause of the universe, eternal happiness is, to the Brahmanical Hind Û , the absorption of the human soul into that cause whence it emanated, never to depart from it again. According to this doctrine, therefore, the liberation of the human soul from transmigration is equivalent to that state of felicity which religion and philosophy attribute to that entity. (See Hinduism). As, however, the ultimate cause of the universe, according to Buddhism. is the void or non-entity, the deliverance from transmigration is to the Buddhists the return to non-entity, or the absolute extinction of the soul. However much, then, the pious phraseology of their oldest works may embellish the state of Nirvana, and apparently deceive the believer on its real character, it cannot alter this fundamental idea inherent in it. We are told, for instance, that Nirvana is quietude and identity, whereas Sansara is turmoil and variety; that Nirvana is freedom from all conditions of existence, whereas Sansara is birth, disease, decrepitude and death, sin and pain, merit and demerit, virtue and vice; that Nirvagna is the shore of salvation for those who are in danger of being drowned in the sea of Sansara; that it is the free port ready to receive those who have escaped the dungeon of existence, the medicine which cures all diseases, the water which quenches the thirst of all desires, etc.; but to the mind of the orthodox Buddhist, all these definitionis convey out the one idea. that the blessings promised in the condition of Nirvana are tantamount to the absolute extinction of the human soul, after it has obeyed in this life all the injunctions of Buddhism, and become convinced of all its tenets on the nature of the world and' the final destination of the soul. There are four paths, an entrance into any of which secures either immediately or more remotely the attainment of Nirvana. They are:
(1) Sowan, which is divided into twenty-four sections; and after it has been entered there can be only seven more births between that period and the attainment of Nirvana, which may be in any world but the four hells.
(2) Sakradagami, into which he who enters will receive one more birth. He may enter this path in the world of men, and afterwards be born in dewaloka; or he may enter it in a dewa-loka, and afterwards be born in the world of men. It is divided into twelve sections.
(3) Anagdmi, into which he who enters will not again be born in a kamaloka; he may, by the apparitional birth, enter into a brahma-loka, and from that world attain Nirvana. This path is divided into forty-eight sections.
(4) Aiya or Aryahat, into which he who enters has overcome or destroyed all evil desires. It is divided into twelve sections. Those who have entered into any of the paths can discern the thoughts of all in the same or preceding paths. Each path is divided into two grades: (a) the perception of the path; (b) its fruition or enjoyment. The mode in which Nirvana, or the destruction of all the elements of existence, may be reached is thus pointed out by Dr. Spence Hardy in his Eastern Monachism: "The unwise being who has not yet arrived at a state of purity, or who is subject to future birth, overcome by the excess of evil desire, rejoices in the organs of sense, ayatana, and their relative objects, and commends them. The ayatanas therefore become to him like a rapid stream to carry him onward towards the sea of-repeated existence; they are not released from old age, decay, death, sorrow, etc. But the being who is purified, perceiving the evils arising from the sensual organs and their relative objects, does not rejoice therein, nor does he commend them, or allow himself to be swallowed up by them. By the destruction of the 108 modes of evil desire he has released himself from birth, as from the jaws of an alligator; he has overcome all attachment to outward objects; he does not regard the unauthorized precepts, nor is he a skeptic; and he knows that there is no ego, no self. By overcoming these four errors he has released himself from the cleaving to existing objects. By the destruction of the cleaving to existing objects he is released from birth, whether as a brahma, man, or any other being. By the destruction of birth he is released from old age, decay, death, sorrow, etc. All the afflictions connected with the repetition of existence are overcome. Thus all the principles of existence are annihilated, and that annihilation is Nirvana."
"Although this is the orthodox view of Nirvana, according to the oldest Buddhistic doctrine, it is necessary to point out two categories of different views which have obscured the original idea of Nirvana, and even induced some modern writers to believe that the final beatitude of the oldest Buddhistic doctrine is not equivalent to the: absolute annihilation of the soul The first category of these latter, or, as we may call them, heterodox views, is that which confounds with Nirvana the preparatory labor of the mind to arrive at that end, and therefore assumes that Nirvana is the extinction of thought, or the cessation, to thought, of all difference between subject and object, virtue and vice, etc., or certain speculations on a creative cause, the conditions of the universe, and so on. All these views Buddha himself rejects, as appears from the work Lankavatadra, which relates his discourse on the real meaning of Nirvana before the Bodhisattwa Mahamati. The erroneousness of these views is obviously based on the fact that the mind, even though in a state of unconsciousness, as when ceasing to think, or when speculating, is still within the pale of existence. Thus, to obviate the mistaken notion that such a state is the real Nirvana, Buddhistic works sometimes use the term Nirupadhis esha Nirvana, or "the Nirvana without a remainder of substratum" (i.e. without a rest of existence), it contradistinction to the "Nirvana with a remainder;" meaning by the latter expression that condition of a saint which, in consequence of his bodily and mental austerities, immediately precedes his real Nirvana, but in which, nevertheless, he is still an occupant of the material world. The second category of heterodox views on the Nirvana is that which, though acknowledging in principle the original notion of Buddhistic salvation, represents, as it were, a compromise with the popular mind. It belongs to a later period of Buddhism, when this religion, in extending its conquests over Asia, had to encounter creeds which abhorred the idea of an absolute nihilism. This compromise coincides with the creation of a Buddhistic pantheon, and with the distribution of Buddhist saints into three classes, each of which has its own Nirvana; that of the two lower degrees consisting of a vast number of years, at the end of which, however, these saints are born again; while the absolute Nirvana is reserved for the highest class of saints. Hence Buddhistic salvation is then spoken of either simply as Nirvana, or the lowest; or as Parinirvacna, the middle; or as Mahtaparinirvana, or the highest extinction of the soul; and as those who have not yet attained to the highest Nirvana must live in the heavens of the two inferior classes of saints until they reappear in this world, their condition of Nirvana is assimilated to that state of more or less material happiness which is also held out to the Brahmanical Hind Û before he is completely absorbed into Brahman. When, in its last stage, Buddhism is driven to the assumption of an Adi, or primitive Buddha, as the creator of the universe, Nirvana, then meaning the absorption into him, ceases to have any real affinity with the original Buddhistic term" (Chambers).
The word itself, as we have seen above, means nothing more nor less than extinction or blowing out. And however much Max Miller may argue against this term as giving expression to Buddha's own gospel, the oldest literature of Buddhism will scarcely suffer us to doubt that Gauama intended in its use to express absolute annihilation, the destruction of all elements which constitute existence. The learned Burnouf (Hist. du Buddhisme, p. 59) takes this ground understandingly, and there is inoit better competent to judge in this question than he is; yet Miller comes forward and, in approving this statement, impeaches its accuracy by stating that the Buddhistic literature truly teaches such a doctrine, but that as Christ's sayings must be held distinct from the writings of the apostles (which we who believe in the inspiration of the Scriptures can hardly understand), so the gospel of Buddhism must be examined apart from the personal utterances of Gautama, who Muller insists never taught the doctrine of annihilation, because "a religion has never been founded by such teaching," and because, too, a man like Buddha, who knew mankind (?), must have known (!) that he could not with such weapons overturn the tyranny of the Brahmans." He therefore concludes thus: "Either we must bring ourselves to believe that Buddha taught his disciples two diametrically opposed doctrines on Nirvana exoteric and esoteric one — or we must allow that view of Nirvana to have been the original view of the founder of this marvelous religion which corresponds best with the simple, clear, and practical character of Buddha." "A very lofty morality" — the Nation (N. Y. Feb. 15, 1872) well answers to this statement of Miller "does not necessarily imply conventionally proper metaphysical opinions, nor is the greatest charity inconsistent with the logical carrying on of one's investigations for their own sake; and it is to be hoped that religious teachers, of all men. should seek to extend their influence rather by what they consider to be the truth than by what might be especially useful as a ‘ powerful weapon.' The last remark sounds strange as coming from one who has studied Buddhism, and is sufficiently refuted by his own words on p. 248, where he shows how in their belief they escaped, by means of Nirvana, transmigration and the misery of living." We might add, this sounds as if Buddha, like Muller, had enjoyed the high plane of Christian ethics, and could have been expected to comprehend the wants of humanity as we now understand them, with the light afforded by Jesus the Christ's teachings and labors. Surely Buddha would do for the Messiah of the world if he could have done and taught as Max Miller would have us believe. The truth is he was simply a philosopher, and fed humanity not upon a relative, but an absolute empty Nothing; a philosophical myth, such as Strauss attempted in the 19th century, but with different motives. In his still more recent publication, as translator of the Dhammapada, or "Path of Virtue," Muller returns to the argument in favor of Gautama's teachings of a hereafter as follows:
" 1. That though the Abhidhamma Pitaka favors the negative view, the affirmative may easily be proved from the Sutta and Vinaya, and especially from the Dhammapada.
2. That the Abhidhamma is of no authority, and contains the notion, not of Buddha, but of his followers.
3. That it is stated that Buddha saw his disciples after attainiing Nirvana, and even after death; and that therefore Nirvana is not extinction of existence.
4. That the expressions used for Nirvana in the Dhammapada convey a sense of rest,. immortality, eternity, etc., and therefore Nirirvna does not mean nihilism."
This statement of his case, which is a more consistent one, has been made the subject of special inquiry by D'Alwis (Review of Max Miller's Dhammapada, Ceylon, 1871), a member of the Royal Asiatic Society, and an Orientalist of no mean order, and the result is its complete refutation. In the first place D'Alwis proves that the Abhidhamma properly belongs to the discourses of Buddha, and that the "three baskets," as the different parts of the code are called, should be regarded as one whole. Moreover. the negative side of the question may be proved from the Sutta and Vinaya. as well as from the Dhammapada; for "the non-existence of an absolute Creator and of a soul was the foundation of the Buddhist doctrine of Nirvana; and therefore there could be no condition of the soul after the final ‘ destruction of the elements and the germs of existence,' or Nirvana." The third point, he shows, rests only on legendary tales, and is in direct contradiction to the canon which professor Muller himself says must be our only authority. The fourth point he disproves at some length by showing the difficulty inherent in all the attempted definitions of Nirvana, the inaccuracy of Max Miller's interpretations, and that the expressions used in the Dhammapada, when taken with the other admitted doctrines of Buddhism, do clearly prove that Nirvana meant nihilism. See Muller, Lectures on the Science of Religion, p. I sq., 131 sq.; id. Chips from a German Workshop, 1:213, 227 sq., 243, 276 sq.; Moffat, Compar. Hist. of Religions, pt. ii, p. 229 sq.; Burnouf, as cited above; Eitel, Three Lectures on Buddhism (Hong Kong, 1871, 8vo), especially p. 21 sq.; Hardwick. Christ and other Masters, 1:233 sq.; Cont. Rev. Jan. 1868, p. 81; and the literature quoted under (See Buddhism) and (See Lamaism).
The Nuttall Encyclopedia 
The name given to the consummation of bliss in the Hindu, but especially the Buddhist, religions, synonymous with extinction, which in the Hindu creed means the extinction of individuality by absorption in the Divine Being, and in Buddhism, not, as some presume, the extinction of existence, but the extinction of agitation of mind through the crucifixion of all passion and desire, the attainment of self-centred, self-sufficient quiescence of being, or rest and peace of soul.