内
Pinyin: nèi
inside; within
Example sentence
三天内给你答复。
Sān tiān nèi gěi nǐ dáfù.
You'll get an answer within three days.
What 内 means
内 (nèi) is an Chinese word meaning “inside; within”. It belongs to the Grammar Words topic and appears at HSK 4, so it is one of the words worth learning early when you study Chinese.