Jack Cole has developed a choreography that contains a jazz-ethnic-ballet style which widely influenced in today's dance style as jazz is used in nightclubs, theater performances, and etc.
In art, a medium is the material that artists use to create their art. It's that simple. Whatever a piece of art is made out of is its medium. The plural of medium is media.
They contain full light with the full range of the spectrum.
It means piece of a body part