dress-upPronunciation: (dres'up"), [key]
being an occasion, situation, etc., for which one must be somewhat formally well-dressed: the first dress-up dance of the season.
a person's best clothes: Wear your dress-ups for the reception.
accessories or other added features: a car with custom dress-ups.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.