This term referred mainly to all the land under the name of the Son of Heaven and the right to rule on such land. The ancient Chinese held that the rule of senior officials was over their enfeoffed land, and that of dukes and princes was over feudal states. The rule of the Son of Heaven was over all the land. Literally, tianxia (天下) means “all under heaven.” It actually refers to all the territory embracing the enfeoffed land and feudal states under the rule or in the name of the Son of Heaven, as well as all the subjects and the right to rule. The term has later evolved to refer to the whole natin or the whole world.
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【引例】
溥天之下,莫非王土;率土之濱,莫非王臣。(《詩經·小雅·北山》)
寡助之至,親戚畔之;多助之至,天下順之。(《孟子·公孫丑下》)
天下興忘,匹夫有責。(梁啟超《飲冰室文集》卷三十三“痛定罪言”三引)
All land under heaven falls within the domain of the Son of Heaven; all those on this land are his subjects. (The Book of Songs)
With little popular support, even his relatives will betray and desert him; but with massive popular support, everyone under heaven will pledge allegiance to him. (Mencius)
The rise and fall of a nation is the concern of every citizen. (Liang Qichao: Collections of lce Drinking Study)