n. A person who likes to be active late at night; a night owl. Syn. -- night owl, nighthawk. [ WordNet 1.5 ]
n. 1. Any loose-fitting clothing for wear in bed. [ PJC ]
2. Especially: a loose dress designed to be worn in bed by women; a nightgown. Syn. -- nightgown, night-robe, nightdress. [ WordNet 1.5 ]