gradus
/ˈgrædəs/noun
(pl. graduses)
- historical a manual of classical prosody formerly used in schools to help in writing Greek and Latin verse〈史〉（旧时学校里写希腊和拉丁文诗句用的）诗韵典。
词源
mid 18th cent.: Latin, from Gradus ad Parnassum 'Step(s) to Parnassus', the title of one such manual.