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night owl

American  
[nahyt oul] / ˈnaɪt ˌaʊl /

noun

Informal.
  1. a person who often stays up late at night; nighthawk.


night owl British  

noun

  1. informal a person who is or prefers to be up and about late at night

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

night owl Idioms  
  1. A person who habitually stays up late and is active at night, as in You can call her after midnight, for she's a night owl. This colloquial term, originally used in the late 1500s for an owl that is active at night, was transferred to nocturnal human beings in the mid-1800s.


Etymology

Origin of night owl

First recorded in 1585–95

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Night owl, from thy words I think that thou art a companion in suffering.

From Tales of Wonder Every Child Should Know by Wiggin, Kate Douglas Smith