In both a republic and a democracy, citizens are empowered to participate in a representational political system. They elect people to represent and protect their interests in how the government functions.
In a republic, an official set of fundamental laws, like the U.S. Constitution and Bill of Rights, prohibits the government from limiting or taking away certain “inalienable” rights of the people, even if that government was freely chosen by a majority of the people.
In a pure democracy, the voting majority has almost limitless power over the minority.
The United States, like most modern nations, is neither a pure republic nor a pure democracy. Instead, it is a hybrid democratic republic.
The main difference between a democracy and a republic is the extent to which the people control the process of making laws under each form of government.