The word sect comes from following, not cutting, despite a Latin mix-up
Most people assume a sect is a group that cut itself off. The Latin root actually meant a road or a way to follow; the cutting sense crept in through confusion with a lookalike word. Sociologists since Max Weber have tried to pin down what separates a sect from a church.
A sect is an offshoot of a larger religious, political or philosophical body that goes its own way in belief and practice. The label first applied only to religious breakaways, but it now stretches to any splinter group. Splits usually follow an accusation of heresy, whether the parent body levels it at the dissenters or the dissenters level it back. In India, by contrast, the word simply names an organised tradition, with no whiff of rebellion.
Etymology holds a small surprise. Secta derives from sequi, to follow, and meant a path, then figuratively a manner of living or a school with its own methods. Another Latin secta, formed from secare, to cut, is unrelated, yet muddling the two shaped many of today's uses.
Max Weber and Ernst Troeltsch, the latter writing in 1912, built the church-sect typology. In their account a church is something you are born into, while a sect is a voluntary association you join by accepting its doctrines and discipline, and your standing must keep being confirmed. Sects often draw members from poorer or marginalised groups and push back against liberal drift in the mainstream, adopting stricter ethics as a kind of protest. Rodney Stark and William Sims Bainbridge stress the high tension a sect keeps with the society around it, since it casts itself as the purified form of the faith it left. Fred Kniss suggests defining a sect by what it opposes: some clash mainly with co-religionists of another ethnicity, others with society at large.
The English sociologist Roy Wallis, in The Road to Total Freedom, argued that sects practise epistemological authoritarianism, meaning some authority decides who is a heretic, and members believe they alone hold the route to truth or salvation. Cults, by his account, lean toward epistemological individualism. Language shifts the tone too: in German, French, Russian and many other European tongues, the local cousin of the word implies a harmful group.
Source: Sect