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

Latest on Legionnaires' disease in Manhattan As of July 19, 74 cases of the disease have been reported to officials, with eight currently hospitalized. — Amethyst Martinez, USA Today, 20 July 2026

According to the Centers for Disease Control and Prevention, about 1 in 10 people diagnosed with Legionnaires' disease die from complications. — Brittany Miller , Stephen Sorace, FOXNews.com, 18 July 2026

From bed bugs to asbestos to now Legionnaires' disease — since returning to the office, California state workers have faced many issues. — Carmela Karcher, CBS News, 14 July 2026

Legionnaires' disease is a form of pneumonia caused by Legionella bacteria, which grow in warm water and can spread in building cooling systems, hot tubs and showerheads. — ABC News, 14 July 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