trope
noun [ C ] uk/trəʊp/ us/troʊp/
art, literature specialized（某位艺术家作品中，或某一类艺术作品中常用的）理念，说法，形象
something such as an idea, phrase, or image that is often used in a particular artist's work, in a particular type of art, etc.
Human-like robots are a classic trope of science fiction. 像人一样的机器人是科幻小说中的典型形象。