中外 (zhōng wài) is a noun meaning 'Chinese and foreign' — it specifically pairs China with other countries, often in formal or official contexts like cultural exchange or cooperation. It differs from 海外 (hǎi wài 'overseas'), which refers to foreign places in general without explicitly including China, and from 内外 (nèi wài 'domestic and foreign'), which can also mean 'inside and outside' in a literal sense.