ratchet/ˈrætʃɪt; `rætʃɪt/ n1 device consisting of a toothed wheel or bar with a catch that fits between the teeth allowing movement in one direction only 棘轮机构.2 (also `ratchet-wheel) wheel that forms part of this device 棘轮. =>illus 见插图.
牛津英汉双解词典