What is contrafact?

Contrafact is a type of jazz composition where the composer takes the basic structure of a popular song, rearranges it and provides a new melody to the song. Charlie Parker was a jazz musician and composer who used this style of composition extensively. Some of the best known examples of Parker's use of contrafact are:
"Ornithology"- Based on the popular song "How High the Moon"
"Moose the Moose"- Based on the standard "I've Got Rhythm"
"Koko"-Based on the swing standard "Cherokee"