Define cults vs. religion

There is no difference except in scale. They both involve the acceptance of an ad hoc "rationality" which extends the boundaries of existence beyond "this life".

Whatever can be said of a cult could have been said at the instigation of any religion. Dawkins would term them both mental viruses the more "successful" of which (tribalistic religions) are transmitted through sociolinguistic norms between generations. Even those who claim "a personal God" but reject organized religion are paying homage to an "ultimate charisma" who serves their desire for "meaning" as the embodiment of "truth" in an otherwise meaningless or painful existence.

Perhaps the most confusing and dangerous religious term is "Cult". The word is derived from the French word "culte" which came from Latin noun "cultus." The latter is related to the Latin verb "colere" which means "to worship or give reverence to a deity." Thus, in its original meaning, the term "cult" can be applied to any group of religious believers: Southern Baptists or Mormons, Jehovah's Witnesses or Catholics, Hindus or Muslims. However, the term has since been assigned at least 7 new and very different meanings. The original meaning of "cult" remains positive; more recent definitions are neutral, negative, or extremely negative:
bullet Positive Meaning:
bullet Theological usage: Oxford English Dictionary defined "cult" as:
bullet "worship; reverential homage rendered to a divine being or beings"
bullet "a particular form or system of religious worship; especially in reference to its external rites and ceremonies"
bullet devotion or homage to a particular person or thing."

This is the historical meaning of the word, but is rarely today heard outside of religious circles. A reference to the "Cult of Mary" appeared in a newspaper report on the Pope's 1999 visit to the Americas. It simply means that the Pope devotes special attention to the Virgin Mary.
bullet Neutral Meanings:
bullet Sociological usage: A small religious group that exists in a state of tension with the predominant religion. Hinduism might be considered a cult in North America; Christianity might be considered a cult in India.
bullet Additional sociological usage: An innovative, fervent religious group, as contrasted with more established and conventional sects and denominations.
bullet The Observer: An English newspaper seemed to use the term to refer to any small religious group, no matter what its age or teachings. 1
bullet General religious usage: A small, recently created, religious organization which is often headed by a single charismatic leader and is viewed as an spiritually innovative group. A cult in this sense may simply be a new religious movement on its way to becoming a denomination. The Christian religion, as it existed in 30 CE might be considered a cult involving one leader and 12 or 70 devoted disciples as followers. The Mormon denomination was started in the 19th century by Joseph Smith and a few followers; it has grown to become an established denomination in excess of ten million members.
bullet Negative Meanings:
bullet Evangelical Christian and Counter-Cult Movement usage: Any religious group which accepts most but not all of the historical Christian doctrines (the divinity of Jesus, virgin birth, the Trinity, salvation, etc.). The implication is that the cult's theology is invalid; they teach heresy. Under this definition, The Church of Jesus Christ of Latter-day Saints (the Mormons), Unification Church and Jehovah's Witnesses to be cults. But they would not classify Wicca as such, because it is not associated with Christianity. The earliest use of this meaning of the word "Cult" is believed to be a 1938 book "The Chaos of the Cults" by J.K. VanBaalen. On the other hand, new religious groups such as the Mormons, Unification Church and Jehovah's Witnesses generally regard themselves to be the true Christian church. They view all other denominations as being in error. Thus, one groups true church is another group's cult.
bullet Fundamentalist Christian usage: Some Fundamentalists would accept the Evangelical definition of cult defined above. Others might brand any religious group which deviates from historical Protestant Christian beliefs as a cult. This definition would include the Mormon Church, Wicca, mainline and liberal Christian denominations, Islam, Hinduism, and all of the other religions of the world. Over 70% of humanity would belong to cults, by this definition.
bullet Mental Health Groups and anti-cult movement usage: A small number of therapists, research psychologists, self-taught individuals, etc., form the anti-cult movement (ACM) They attempt to raise public consciousness about what they see as dangerous and authoritarian mind control cults and doomsday cults. Many do not care about the faith group's theology. They target only what they see as deceptive practices, and dangerous psychological pressure techniques, such as brainwashing. The ACM appears to hold opinions about the effectiveness of brainwashing that are not shared by the mental-health community generally. They see mind control/doomsday cults as a widespread social problem.
bullet Very negative meaning:
bullet Popular, media usage: (very negative meaning) a small, evil religious group, often with a single charismatic leader, which engages in brainwashing and other mind control techniques, believes that the end of the world is imminent, and collects large amounts of weaponry in preparation for a massive war. Often used as a synonym for mind control religious group or for doomsday cult. The earliest use of this meaning of the word is believed to have been in a 1965 book by Walter Martin "The Kingdom of the Cults" (revised and expanded posthumously by Hank Hanegraaff in 2002).

We have seen "cult" used to refer to Evangelical denominations, the Roman Catholic Church, Unification Church, Church of Scientology, United Church of Christ, The Church of Jesus Christ of Latter-day Saints, Wiccans, other Neopagans and many other faith groups. The term is essentially meaningless.

http://www.religioustolerance.org/cults.htm