Merriam-Webster Logo
  • Dictionary
  • Thesaurus
  • Scrabble
  • Spanish Central
  • Learner's Dictionary

Medical Dictionary

Spanish flu

noun Span·ish flu \ˈspan-ish-\

Medical Definition of Spanish flu

  1. :  influenza that is caused by a subtype (H1N1) of an orthomyxovirus (species Influenza A virus of the genus Influenzavirus A) and that was responsible for about 500,000 deaths in the U.S. in the influenza pandemic of 1918–1919 <Between 20 million and 40 million died around the globe of the Spanish flu of 1918, probably the worst pandemic in human history.—Douglas M. Birch, Baltimore Sun, 16 Dec. 1997>—compare asian flu, hong kong flu

Variants of spanish flu


Spanish influenza

Seen and Heard

What made you want to look up Spanish flu? Please tell us where you read or heard it (including the quote, if possible).


looking or feeling very sad

Get Word of the Day daily email!