Nike's swoosh. McDonald's golden arches. The name "Google." These are trademarks: words, symbols, sounds, even colors that identify the source of goods or services. A trademark does not protect an invention. It protects a brand's identity in the marketplace. The goal is to prevent confusion. If you see a swoosh on a shoe, you expect Nike quality, not a knockoff from a basement factory.

Rights can arise through use or registration. In the United States, you can establish common law rights simply by selling goods under a mark. Federal registration with the USPTO adds nationwide priority and the ability to sue in federal court. In China, registration comes first. File early or lose the name to someone else.

What can be trademarked

• Words and slogans: "Just Do It."
• Logos and designs: the Apple bitten apple.
• Sounds: the MGM lion roar.
• Colors: Tiffany blue, under certain conditions.

Trademarks can last forever if renewed and used. They can also be lost. Aspirin, escalator, and zipper were once trademarks. They became generic because owners failed to police them. Xerox and Google fight daily to avoid that fate.