Orthodoxy, translated literally, is “right praise.” In time, it came to mean “sound doctrine” and regularly conveys, more simply, “conforming to the norm.” When something is orthodox it is approved, conventional, standard practice, acceptable. The opposite of orthodox is, not surprisingly, unorthodox or, more technically speaking, heterodox. Heterodoxy literally means “different praise” or, more typically, “unsound or controversial doctrine” and “contrary to popular practice.” If “heterodoxy” is a mouthful or sounds a little unfamiliar, you might be better acquainted with its most extreme form, “heresy,” which...