I can't believe this needs to be clarified...
From https://www.merriam-webster.com
democracy: a : government by the people; especially : rule of the majority
b : a government in which the supreme power is vested in the people and exercised by them directly or indirectly through a system of representation usually involving periodically held free elections
republic: a (1) : a government having a chief of state who is not a monarch and who in modern times is usually a president (2) : a political unit (such as a nation) having such a form of government
b (1) : a government in which supreme power resides in a body of citizens entitled to vote and is exercised by elected officers and representatives responsible to them and governing according to law (2) : a political unit (such as a nation) having such a form of government
These are not incompatible. In fact, the definitions have a lot of overlap and the US system fits both definition. The fact that we elect representatives to legislate rather than have the people legislate directly still fits the definition of democracy.
It's a Democratic Republic.
4 ≈ One