n. 1. A person who likes to be active late at night; a night owl. Syn. -- night owl, nightbird. [ WordNet 1.5 ]
2. (Zool.) Any of several mainly nocturnal North American goatsuckers, especially Chordeiles minor, or the related European goatsucker Caprimulgus europaeus, also called the nightjar. Syn. -- bullbat, mosquito hawk. [ WordNet 1.5 ]