This is the registrability chapter of UpLaw's trademark overview, and it answers the question that quietly decides most trademark disputes before the parties ever reach confusion or damages: which designations the law is willing to treat as property, and which it turns away. The article opens with the two affirmative requirements every mark must meet--distinctiveness, mapped along the Abercrombie spectrum from generic to fanciful, and use in commerce--then works through the doctrine of secondary meaning that lets a weak term grow into a protectable one. From there it walks the statutory gauntlet of Lanham Act Section 2: mere descriptiveness and deceptive misdescriptiveness under Section 2(e)(1), the geographic bars of Section 2(e)(2) and (3), the surname bar of Section 2(e)(4), the failure-to-function and ornamentation refusals, the functionality doctrine that keeps useful features out of trademark law, the likelihood-of-confusion bar of Section 2(d), and the Section 2(a) and 2(c) bars reshaped by Matal v. Tam, Iancu v. Brunetti, and Vidal v. Elster. Each bar comes with the test examiners and courts actually apply, the authorities that supply it, and fresh worked hypotheticals. Read it beside the subject-matter, registration, and enforcement chapters of the overview.