Legionnaires' disease

noun

Le·​gion·​naires' disease ˌlē-jə-ˈnerz- 

variants or less commonly Legionnaire's disease

: pneumonia that is caused by a bacterium (Legionella pneumophila), is characterized initially by symptoms resembling influenza (as malaise, headache, and muscular aches) followed by high fever, cough, diarrhea, severe pneumonia, and mental confusion, and that may be fatal especially in elderly and immunocompromised individuals

Examples of Legionnaires' disease in a Sentence

Recent Examples on the Web

The South Bronx was also the epicenter of the city's deadliest Legionnaires' disease outbreak on record, which happened in 2015. — Jesse Zanger, CBS News, 17 Sep. 2026

New York City is experiencing another cluster of Legionnaires' disease just weeks after a cluster exposure in Manhattan was declared over. — Youri Benadjaoud, ABC News, 11 Sep. 2026

Legionnaires' disease outbreak claims two new deaths Alister Martin, the NYC Health Commissioner, announced that after investigation, two additional deaths would now be added to the overall count. — Amethyst Martinez, USA Today, 31 Aug. 2026

Word History

Etymology

from its first recognized occurrence at an American Legion convention in 1976

First Known Use

1976, in the meaning defined above

Rhymes for Legionnaires' disease

• idiosyncrasies
• abcs
• absentees
• addressees
• adoptees
• allottees
• amputees
• antifreeze
• appellees
• appointees
• arrestees
• artistes

Medical Definition

Legionnaires' disease

noun

variants also Legionnaire's disease

: pneumonia that is caused by a bacterium of the genus Legionella (L. pneumophila), that is characterized initially by symptoms resembling influenza (as malaise, headache, and muscular aches) followed by high fever, cough, diarrhea, lobar pneumonia, and mental confusion, and that may be fatal especially in elderly and immunocompromised individuals see pontiac fever