You can do a Trademark Search at the US Patent Office. It is smart to do such a search before launching a project.

People can establish an intent to use a term as a Trademark simply by putting a trademark symbol ™ by the term. I like to do this when I start a project just to keep others from trademarking the term I want to use.

Some people try to stifle web development with bogus trademark claims.

I bought the domain ArizonaColor.US. I was contacted by the lawyer of the company who bought the ArizonaColor.com domain a day before me. A shyster lawyer claimed that getting the dot com domain gave his client the trademark.