When the Founding Fathers of the United States set about forming a new nation, for obvious reasons they wanted to ensure that the executive could have neither the potential nor the pretensions of tyranny. So in addition to setting in place all of the checks and balances we learn are integral to the U.S. political system, they made a conscious effort to devise a new and unusual term for their head of government: President, derived from the Latin prae- “before” plus sedere “to sit”.
Up until that point, a president was someone originally tasked with presiding over (e.g., sitting before) a gathering or ceremony to ensure that everything runs smoothly. It was largely limited to academia, and was hardly an authoritarian position — which of course was precisely the point. The executive of the United States was not vested with anything more than the power to help enforce the laws of Congress, and to essentially preside over a system of power wherein the people, via their representatives, governed themselves.
(Interestingly, several countries, such as Germany and India, have offices of the president that are truer to the original etymology of the term: their presidents are mostly figureheads with few actual powers in paper and in practice.)
Granted, all this was pretty idealistic and aspirational, and as we all know, the office of the president has not always been true to its original spirit; indeed, even back then there was debate as to how much authority or power the president should have, and it was not long before presidents of all political stripes started pushing the boundaries of executive power. But it is interesting to see how even semantics could be an important consideration in formulating a political system.