Webster's Dictionary 
(n.) The religion based upon the doctrine originally taught by the Hindoo sage Gautama Siddartha, surnamed Buddha, "the awakened or enlightened," in the sixth century b. c., and adopted as a religion by the greater part of the inhabitants of Central and Eastern Asia and the Indian Islands. Buddha's teaching is believed to have been atheistic; yet it was characterized by elevated humanity and morality. It presents release from existence (a beatific enfranchisement, Nirvana) as the greatest good. Buddhists believe in transmigration of souls through all phases and forms of life. Their number was estimated in 1881 at 470,000,000.
The Nuttall Encyclopedia 
The religion of Buddha, a religion which, eschewing all speculation about God and the universe, set itself solely to the work of salvation, the end of which was the merging of the individual in the unity of being, and the "way" to which was the mortification of all private passion and desire which mortification, when finished, was the Buddhist Nirvâna. This is the primary doctrine of the Buddhist faith, which erelong became a formality, as all faiths of the kind, or of this high order, ever tend to do. Buddha is not answerable for this, but his followers, who in three successive councils resolved it into a system of formulæ, which Buddha, knowing belike how the letter killeth and only the spirit giveth life, never attempted to do. Buddha wrote none himself, but in some 300 years after his death his teachings assumed a canonical form, under the name of Tripitaka, or triple basket, as it is called. Buddhism from the first was a proselytising religion; it at one time overran the whole of India, and though it is now in small favour there, it is, in such form as it has assumed, often a highly beggarly one, understood to be the religion of 340 millions of the human race.