The term SLUMBER PARTY ATTIRE can be summarized by two crossword solutions: PAJAMAS (7 letters) and PJS (3 letters). PAJAMAS are loose-fitting garments traditionally worn for sleeping and lounging. They usually consist of a shirt and pants, and sometimes a robe. PJS is an abbreviation for PAJAMAS. Slumber parties are a popular activity among children and teenagers, and wearing PAJAMAS is a common part of the experience.