one of a set of narrow pieces of wood, plastic, etc. in a door or a window that are designed to let air and some light in, but to keep out strong light or rain; a door or a window that has these narrow pieces across it 百叶窗板;百叶门;百叶窗 Word OriginMiddle English (originally meaning a rough structure incorporating openings to let out smoke): from Old French lover, lovier ‘skylight’, probably of Germanic origin and related to lodge.