night-owl (n.)youdaoicibaDictYouDict[night-owl 词源字典]
"owl which flies at night," 1590s; applied since 1846 (American English) to persons who are up or out late at night. Compare night-hawk, also French hirondelle de nuit "prostitute," literally "night-swallow."[night-owl etymology, night-owl origin, 英语词源]