What is the difference between a DBA and a trademark?

Trademarks and DBA names serve two different purposes. A DBA registration allows you to conduct business in a name other than your own (or your company’s) legal name, and allows others to identify the person or entity behind the business name you've registered. 

In contrast, you register a trademark to identify the goods or services you're selling and to distinguish them from the goods and services of others. A company that files a DBA name does not have exclusive rights to the registered name—and in fact may not even be able to use it legally in commerce if it violates another company’s trademark. 

Trademarks, on the other hand, grant a business the exclusive right to use the mark, words, symbols, or title in commerce.  A DBA or corporate legal name generally conveys very few legal rights, and registering it doesn't protect it from future use by another business. In contrast, a federally registered trademark allows you legally to force other entities to stop using the mark or a similar mark that would confuse consumers.