In the United States, a prom, short for promenade, is a formal dance held at the end of the years of high school and college, called junior prom and senior prom respectively. In British English such an event would be called a ball, although in Canada, Australia, and New Zealand it is also often called a formal. In Australian schools the terms used are either formal or sometimes as Leaver's Dinner, usually so when the night includes a meal. In Ireland it is known as a debs (an abbreviation of debutante ball). In the U.S. a "formal" is typically a similar dance that is held by a fraternity or sorority affiliated with a certain college or university. In Australia, the term "prom" has also come into sparse usage and in Britain it is becoming widespread, because of US influence. The name is derived from the late ninteenth century practice of a Promenade ball. The end of year tradition stemmed from the Graduation Ball tradition.

The state was named after the Spanish word "Colorado," which means "reddish colored" that presumably refers to the red sandstone formations in the area or reddish brown color of the Colorado River.

The territory that ultimately became Colorado was added to the United States by the 1803 Louisiana Purchase and the 1848 Mexican Cession. The Colorado Gold Rush of 1859 brought many settlers to the Denver area, though the population collapsed following an initial mining boom. The Colorado Territory was organized as a United States territory on February 28, 1861, and Colorado attained statehood August 1, 1876, (earning it the moniker the "Centennial State"). Colorado women were granted the right to vote starting on November 7, 1893.

Source: http://en.wikipedia.org/