noun · a wide gap, chasm, or deep divide, often used figuratively to describe social, economic, or ideological differences

贫富之间的鸿沟正在不断扩大。

place name · the historical canal in Henan that served as the border between the rival states of Chu and Han during the Chu-Han Contention

历史上，鸿沟曾是楚汉两军对垒的分界线。