Actually it is the University of Colorado. Several regional schools follow the same switch in abbreviation including KU, MU, NU, and OU. Each are the "University of" their respective states.
forgot the University of Kansas: KU.
All of the original Big-8 schools without a "state" in their names reverse their initials. Colorado, Missouri, Nebraska, and Oklahoma are CU, MU, NU, and OU respectively. There is no UC Boulder. It is CU Boulder.