grammar: the branch of linguistics that deals with syntax and morphology (and sometimes also deals with semantics)
abstraction: a general concept formed by extracting common features from specific examples
manichaeism: a religion founded by Manes in the third century; a synthesis of Zoroastrian dualism between light and dark and Babylonian folklore and Buddhist ethics and superficial elements of Christianity; spread widely in the Roman Empire but had largely died out by 1000