pneu·​mo·​coc·​cus | \ ˌnü-mə-ˈkä-kəs How to pronounce pneumococcus (audio) , ˌnyü-\
plural pneumococci\ ˌnü-​mə-​ˈkäk-​ˌsī How to pronounce pneumococci (audio) , -​ˌsē ; -​ˈkä-​ˌkī , -​ˌkē , ˌnyü-​ \

Definition of pneumococcus

: a bacterium (Streptococcus pneumoniae) that causes an acute pneumonia involving one or more lobes of the lung

Keep scrolling for more

Other Words from pneumococcus

pneumococcal \ ˌnü-​mə-​ˈkä-​kəl How to pronounce pneumococcal (audio) , ˌnyü-​ \ adjective

Examples of pneumococcus in a Sentence

Recent Examples on the Web

The pneumococcus bacteria can cause deadly secondary infections, especially in older people who get the flu or whooping cough. Paul Sisson,, "Which vaccines do home caregivers need?," 24 Apr. 2018 Bacterial meningitis is often caused by pneumococcus, which can be prevented by vaccine. Lynne Terry,, "Gresham mom, 36, gets flu; days later she dies," 24 Jan. 2018 But when our defenses fail us, pneumococcus can migrate, multiply, and set off life-threatening infectious disease. Annabelle Timsit, The Atlantic, "Drugs in Afghanistan and Vaccines in Bangladesh: The Week in Global-Affairs Writing," 27 Oct. 2017 Mrs. Clinton’s pneumonia affects her right lung’s middle lobe, according to Dr. Bardack, a location that suggests that it was caused by bacteria, commonly pneumococcus. Lawrence K. Altman, M.d., New York Times, "How Healthy Is Hillary Clinton? Doctors Weigh In," 18 Sep. 2016

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'pneumococcus.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

See More

First Known Use of pneumococcus

1885, in the meaning defined above

History and Etymology for pneumococcus

New Latin

Keep scrolling for more

Learn More about pneumococcus

Statistics for pneumococcus

Look-up Popularity

Time Traveler for pneumococcus

The first known use of pneumococcus was in 1885

See more words from the same year

Keep scrolling for more

More Definitions for pneumococcus


pneu·​mo·​coc·​cus | \ ˌn(y)ü-mə-ˈkäk-əs How to pronounce pneumococcus (audio) \
plural pneumococci\ -​ˈkäk-​ˌ(s)ī How to pronounce pneumococci (audio) \

Medical Definition of pneumococcus

: a bacterium of the genus Streptococcus (S. pneumoniae) that causes an acute pneumonia involving one or more lobes of the lung

More from Merriam-Webster on pneumococcus Encyclopedia article about pneumococcus

Comments on pneumococcus

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


standardized text or formulaic language

Get Word of the Day daily email!

Test Your Vocabulary

Finance Words Quiz

  • a-piggy-bank
  • The etymology of mortgage is related most closely to which two words?
Spell It

Can you spell these 10 commonly misspelled words?

Bee Cubed

Test Your Knowledge - and learn some interesting things along the way.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!