A “cult” means different things dependence on the context. Theologically or religiously, there isn’t any definition: a “cult” is simply a buzzword with a negative connotation used to portray other religions negatively.
Academically, “cult” has two meanings: the first might be understood as a synthesis between devotion and ritual. For example, when analyzing global Catholics, we might look at the “cult of Mary.” This isn’t to imply anything evil or morally wrong with devotion to Mary – or even to pass judgement or theological statements about it – but rather to imply a sort of system-within-a-system.
The second is the one you find in sociological papers. “Cult” becomes a type of movement, alongside “sect,” “denomination,” and “religion.” Religion is the broad category; a denomination is a smaller category; a sect is a schismatic category, and sometimes used interchangeably with “new religious movement.”
A “cult” here has six qualities, which a previous poster succinctly reduced to four.
I’m a Baha’i. So I don’t recognize any other Baha’i groups exist, theologically/religiously/personally. So any group claiming to be Baha’i I’d probably think of as a “cult.”
But as an academic this is more complicated. A pair of sociologists spent some time with a 40-member group in Colorado (the full PDF is available on JSTOR for anyone with access to a university library) who were “Baha’i,” but believed the end of the world was imminent. These persons surrounded a central, authoritarian leader and devoted much of their wealth to build a type of stronghold. When the end-of-the-world prophecy failed, most of these people left their group, I think becoming Christians and atheists. Sociologically, this movement was a “cult.” Additionally, there is a group calling itself the “Orthodox Baha’i Faith” that follows a different leadership. It’s relatively small, but open. They like to purchase followers on social media to give the impression that they are much larger than they are; a sort of advertising. Sociologically speaking, this group would be a “sect” or “schismatic,” but not a cult.