四海(shǎi)
全国各地或世界各地。古人认为中国的疆域四面环海，各依方位称东海南海西海和北海，合称四海。它蕴含着远古中国人关于中国和世界的地理图景：九州居天下之中，天下由九州及其周边四海组成，中国是海内，外国则是海外。在古人那里，四海大多统指天下，并不确指某个海域，有时用来指陆地四周的海，有时又指四海所环绕的陆地。
Four Seas
Four Seas refer to the territory of China or the entire world. The ancient Chinese believed that China was a land surrounded by Four Seas the East, West, North, and South seas. The term suggests what the ancient Chinese conceived to be the map of China and the world: Nine zhou (regions) were located at the center of tianxia (all under heaven). Tianxia consisted of nine zhou and its surrounding Four Seas. China was within the Four Seas, while foreign lands were outside the Four Seas. In ancient China, Four Seas referred to all under heaven in most cases, and did not denote a specific body of water. Therefore, the term was used sometimes to mean the seas surrounding the land, and sometimes to specify the land surrounded by the Four Seas.
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【引例】
君子敬而无失，与人恭而有礼，四海之内皆兄弟也。(《论语颜渊》)
A man of virtue always does things conscientiously without making any mistakes and treats people respectfully and appropriately. Then all within the Four Seas will be his brothers. (The Analects)