A trademark is not a name you own. It is a right to stop other people from confusing your customers, and it exists only where you actually use the mark and only where confusion is likely. This article explains the distinctiveness spectrum that determines whether a name is protectable at all, and why the name that best describes what you sell is usually the worst name to choose. It covers how rights are acquired by use rather than registration, what federal registration adds, and why registration is still worth the money. It explains likelihood of confusion as courts actually apply it, and the surprising cases that decide the edges: whether a color can be a mark, when product design is protected, why adding dot-com can save a generic term, and how a dog toy shaped like a whiskey bottle came out. It closes with the two ways trademarks die — genericide and abandonment — and what an owner must actually do to keep one alive.