Stories We Like: A Guide to the Comma
mid-14c., "distinctive system of beliefs or observances; party or school within a religion," from Old French secte, sete "sect, religious community," or directly from Late Latin secta "religious group, sect in philosophy or religion," from Latin secta "manner, mode, following, school of thought," literally "a way, road, beaten path," from fem. of sectus, variant past participle of sequi "follow," from PIE *sekw- (1) "to follow" (see sequel). Confused in this sense with Latin secta, fem. past participle of secare "to cut" (see section (n.)). Meaning "separately organized religious body" is recorded from 1570s.
A religious group, especially one that has separated from a larger group. Sect is often a term of disapproval.
(Gr. hairesis, usually rendered "heresy", Acts 24:14; 1 Chr. 11:19; Gal. 5:20, etc.), meaning properly "a choice," then "a chosen manner of life," and then "a religious party," as the "sect" of the Sadducees (Acts 5:17), of the Pharisees (15:5), the Nazarenes, i.e., Christians (24:5). It afterwards came to be used in a bad sense, of those holding pernicious error, divergent forms of belief (2 Pet. 2:1; Gal. 5:20).