When you apply to register a trademark with the United States Patent and Trademark Office (USPTO), in almost all cases you’ll be applying to have the mark placed on the Principal Register of Trademarks. This will give you all of the rights one associates with a trademark registration. However, in some cases, the mark is not eligible for placement on the Principal Register, but it is eligible for placement on the USPTO’s Supplemental Register. What does that actually mean? Which Trademarks Are Not Eligible for Registration on the Principal Register? A mark that can’t be placed on the Principal Register, but…