John Adams:

Scarcely any two writers, much less nations, agree in using words in the same sense. Such a latitude, it is true, allows a scope for politicians to speculate, like merchants with false weights, artificial credit, or base money, and to deceive the people, by making the same word adored by one party, and execrated by another. The union of the people, in any principle, rule, or system, is thus rendered impossible; because superstition, prejudice, habit, and passions, are so differently attached to words, that you can scarcely make any nation understand itself. The words monarchy, aristocracy, democracy, king, prince, lords, commons, nobles, patricians, plebeians, if carefully attended to, will be found to be used in different senses, perpetually, by different nations, by different writers in the same nation, and even by the same writers in different pages.