“Use in commerce” is a term in trademark law. In the United States and some other countries, trademark rights are created by using the trademark in connection with goods and services in commerce. “In commerce” here means any commerce that Congress can regulate, which typically means goods or service sold in interstate* or international commerce. Usually it is very clear that a trademark is being used in commerce – if a good is sold regularly sold across state lines, then it is being used in commerce. There can be edge cases, however.

What does not count as use in commerce is advertising, though. If you are planning a big advertising or crowdfunding campaign prior to launching your product, you should be aware that you will not be developing trademark rights in this period. You should consider an intent-to-use trademark application in this case.

*Interstate commerce is usually important because most trademark disputes will take place at the federal level, which for constitutional reasons is limited to cases involving interstate commerce. Most trademarks will be considered interstate commerce even if no sales are made outside of the state, though. In the rare occasion where the interstate commerce requirement is not met, intrastate commerce may establish trademark rights in the state where the business is operating.