Despite whatever desire individuals or groups may have to change the meaning of words, words do have meanings and definitions. I realize knowledge of civics is lacking in the U.S., but there are still dictionaries.
The United States and every other country in which people choose their representatives thru elections is a democracy. In the U.S., democracy may be direct at the local or state level, such as voting for ballot measures, bond issues, local government modifications, or state constitutional amendments or indirect thru the election of representatives to legislative bodies. In either case, the choices are made by the people thru the
democratic process of voting. To deny that the U.S. is a democracy is ridiculous. This also applies to any other nation with a reasonably free, fair, and functioning elected system of government in which the people make choices thru voting.
https://www.merriam-webster.com/dictionary/democracySince the the United States doesn't have a monarch or dictator that rules, it is also a republic. It is also a federation, as are
several other nations. It is also governed by a federal constitution which, like other federations, has supremacy over state constitutions.
The United States is a democracy, a republic, a federation, and governed by a supreme federal constitution. It is each of those things and all of those things—as no one of those precludes the U.S. system of government from being any or all of the others mentioned. The complete U.S. form of government is a constitutionally governed-federal-democratic-representative republic.
Unfortunately, when democracy is threatened it endangers all of the other pillars of self-government.