Are yams and sweet potatoes the same?
mid-15c., "of this world," from Old French mondain "of this world, worldly, earthly, secular;" also "pure, clean; noble, generous" (12c.), from Late Latin mundanus "belonging to the world" (as distinct from the Church), in classical Latin "a citizen of the world, cosmopolite," from mundus "universe, world," literally "clean, elegant"; used as a translation of Greek khosmos (see cosmos) in its Pythagorean sense of "the physical universe" (the original sense of the Greek word was "orderly arrangement"). Latin mundus also was used of a woman's "ornaments, dress," and is related to the adjective mundus "clean, elegant" (used of women's dress, etc.). Related: Mundanely.