Trademark vs. registered business name: what's the difference?

A lot of founders assume that registering their company locks up the name. It doesn't. There are three separate systems at work, and each does something different:

• Entity name: the name your LLC or corporation is registered under with a state. It mostly ensures no other company in that state forms under the identical name. It's not a nationwide brand right.

• DBA / "doing business as": a registered trade name letting you operate under something other than your legal entity name. It's a disclosure filing, not a source of exclusive rights.

• Trademark: a federal (or state) right in a name or logo as a source identifier for particular goods or services. This is the one that lets you stop others nationwide from using a confusingly similar mark on related products.

The trap is thinking a state LLC registration protects your brand. It doesn't. Two things can be true at once: your LLC is validly registered in your state and your brand name infringes someone's federal trademark. Registering the entity checks a state's company roster; it does not check the federal trademark register, and it grants no nationwide brand rights.

The reverse is also true: you can hold a trademark without any particular entity name, because the trademark attaches to the mark-and-goods, not to your company's legal name.

Because they're separate systems, they need separate checks: the state's business-entity database for the entity name, and the trademark register for brand conflicts. If you care about the brand (the thing customers recognize), the trademark side is the one that determines whether you can safely build on the name.