Back in the 1920's the word "Flapper" was coined to describe to women who danced the latest craze; the Charleston. The term was derived from the movements associated with the dance steps that required that the woman would flap their arms & walk like birds - hence Flappers as in flapping wings of the birds. Although the dance was popularized during the 1920's, the earliest Charleston is believed to have been part of several Harlem (USA) stage shows being recorded as early as 1913.
Jersey fabric: In 1916, Gabrielle "Coco" Chanel outraged the fashion industry by using jersey at a time when it was strictly associated with underwear. "This designer made jersey what it is today - we hope she's satisfied," snapped Vogue in 1917. "It's almost as much part of our lives as blue serge is."