The Bahá'í Faith is a monotheistic religion founded by Bahá'u'lláh in 19th-century Persia, emphasizing the spiritual unity of all humankind. There are an estimated five to six million Bahá'ís around the world in more than 200 countries and territories.
In the Bahá'í Faith, religious history is seen to have unfolded through a series of divine messengers, each of whom established a religion that was suited to the needs of the time and the capacity of the people. These messengers have included Abraham, the Buddha, Jesus, Muhammad and others, and most recently the Báb and Bahá'u'lláh. In Bahá'í belief, each consecutive messenger prophesied of messengers to follow, and Bahá'u'lláh's life and teachings fulfilled the end-time promises of previous scriptures. Humanity is understood to be in a process of collective evolution, and the need of the present time is for the gradual establishment of peace, justice and unity on a global scale.
The word "Bahá'í" is used either as an adjective to refer to the Bahá'í Faith or as a term for a follower of Bahá'u'lláh. The word is not a noun meaning the religion as a whole. It is derived from the Arabic Bahá, meaning "glory" or "splendour". The term "Bahaism" (or "Baha'ism") has been used in the past, but the generally accepted name for the religion is the Bahá'í Faith.
Source: Wikipedia, "Bahá'í Faith", available under the CC-BY-SA License.