A plume dancer was a type of dancer native to the planet Macedon III.
Plume dancers were considered to be a tourist attraction to off-worlders and when Lieutenant Lex Nakashima heard that the USS Enterprise was taking liberty on Macedon III, it was one of many attractions that he listed while in conversation with Doctor Leonard McCoy and Lieutenant Commander Nyota Uhura. (TOS - Star Trek II Short Stories short story: "Under Twin Moons")