haireisis

Haireisis (Greek αἵρεσις) is an ancient Greek term with a broad semantic range centered on choice and opinion. The core sense is “a choosing” or “a course of thought,” and the word develops from a root meaning “to choose” or “to take for oneself.” In classical and Hellenistic Greek, haireisis could refer to an opinion, stance, or the various philosophical or political schools within a debate, i.e., a sect or faction.

In late antiquity and the patristic period, haireisis gained a more technical sense within religious discourse. It came to denote a school of thought or doctrine, and in Christian usage it increasingly designated beliefs or movements regarded as divergent from orthodox teaching. From this history, haireisis is commonly translated as “heresy” or, when referring to a group, as “sect.” In the New Testament and early Christian literature, the term is used to describe factions or opinions within Judaism or Christianity, often in polemical contexts.

Modern scholarship treats haireisis as a historically neutral term that evolved from general meaning of opinion or school to a term with religious significance. Distinctions are made between neutral philosophical schools and the pejorative senses of doctrinal deviation associated with later “heresy.” In contemporary Greek, haireseis (plural) remains the standard word for “heresies” and for historical sects; in English, haireisis or haireseis is used mainly in scholarly discussion, with “heresy” as the ordinary translation in Christian contexts.