If your Chinese is at a moderate level, there’s a good chance you’ll have learned the word 老百姓 (lit. “old hundred names” or “the common people”). What you may not have learned is that the word has completely flipped in meaning over the last hundred years. Throughout most of Chinese history, common people did not have surnames. Surnames (姓) were reserved only for the aristocracy, and the “hundred” (百) was a way of referring to all of the various family lines as a unit. Thus, 百姓 refers to the nobility, not the common people. However with the end of the feudal system, the universalization of surnames, and progressive social atmosphere brought by the communist revolution, the term took a 老 (“old”, which to this learner seems to add both respect and familiarity) and began to refer to “the people” as a whole.