Definition of "Cult" :

noun: an interest followed with exaggerated zeal

noun: a system of religious beliefs and rituals

"Devoted to the cultus of the Blessed Virgin."

noun: a religion or sect that is generally considered to be unorthodox, extremist, or false

"It was a satanic cult."

noun: followers of an unorthodox, extremist, or false religion or sect who often live outside of conventional society under the direction of a charismatic leader

noun: followers of an exclusive system of beliefs and practices