Chiffon was a soft, transparent fabric used to make fancy clothes.
Jo Grant wore a scarlet chiffon scarf when she first met Mark IV Daleks including a gold leader as well as their Controller and Ogrons during the Time Paradox Incident; (TV: Day of the Daleks) and when helping many versions of the Doctor and companions. (GAME: Lost in Time)
Martha Jones wore a dress of dark mauve purple chiffon when she and the Tenth Doctor met Lazarus. (TV: The Lazarus Experiment)