"ornamental grating," 1660s, from French grille (fem.) "grating," from Old French greille "gridiron," from Latin craticula "gridiron, small grill" (see grill (n.)). "The distinction in Fr[ench] between grille and grill ... appears to date from about the 16th c." [OED].[grille etymology, grille origin, 英语词源]