c. 1300, "district with its own church; members of such a church," from Anglo-French paroche, parosse (late 11c.), Old French paroisse, from Late Latin parochia, paroecia "a diocese," an alteration of Late Greek paroikia "a diocese or parish," from paroikos "a sojourner" (in Christian writers), in classical Greek, "neighbor," from para- "near" (see para- (1)) + oikos "house" (from PIE root *weik- (1) "clan").
The sense development of the word in the early Church is unclear, perhaps it is from "sojourner" used as epithet of early Christians as spiritual sojourners in the material world. In early Church writing the word was used in a more general sense than Greek dioikesis, though by 13c. they were synonymous. It replaced Old English preostscyr, literally "priest-shire." In Great Britain (from the 1630s), some southern American colonies, and Louisiana it has been the name for a purely civil division for purposes of local government, with boundaries originally corresponding to an ecclesiastical parish.