N-COUNT
（文件、論點(diǎn)等中對(duì)重要問題的）缺漏，脫漏，遺缺
If you say that there is a lacuna in something such as a document or a person's argument, you mean that it does not deal with an important issue and is therefore not effective or convincing.
例句
There are still major lacunae in the material available.
手邊的材料依然存在嚴(yán)重缺漏。