"ZIP Code" was originally trademarked, but I believe it has expired now. The State of New Jersey actually sued a Florida pizza place for trademark violations:

"ZIP Code" was originally trademarked, but I believe it has expired now. The State of New Jersey actually sued a Florida pizza place for trademark violations: https://www.nbcnewyork.com/news/local/New-Jersey-Loses-Trademark-Fight-With-Florida-Pizza-Shop-Over-Logo-482917131.html https://www.nbcnewyork.com/news/local/New-Jersey-Loses-Trade... they lost, however, because nobody ever confused a Florida pizza place with a New Jersey highway.