Three large cities — Dallas, Fort Worth, and Arlington — make up this area. Each city is linked by bordering city limits or suburbs. The area is also known as the Dallas–Fort Worth “metroplex”, so called because has more than one principal anchor city of nearly equal size or importance, and is included in the emerging megalopolis known as the Texas Triangle. According to "Texas Monthly", the term is a portmanteau of the terms "metropolitan" and "complex" and was created by local advertising agency TracyLocke. The North Texas Commission trademarked the term "Dallas/Fort Worth Metroplex" in 1972 as a replacement for the previously ubiquitous term "North Texas". Urban areas with smaller secondary anchor cities (such as Mexico City, New York City, Los Angeles, Houston, Chicago and Phoenix) are not considered to be conurbations.