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pathogen

American  
[path-uh-juhn, ‑-jen] / ˈpæθ ə dʒən, ‑ˌdʒɛn /

noun

  1. any disease-producing agent, especially a virus, bacterium, or other microorganism.


pathogen British  
/ ˈpæθəˌdʒiːn, ˈpæθəˌdʒɛn /

noun

  1. any agent that can cause disease

"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

pathogen Scientific  
/ păthə-jən /
  1. An agent that causes infection or disease, especially a microorganism, such as a bacterium or protozoan, or a virus.

  2. See Note at germ


pathogen Cultural  
  1. A disease-causing agent. Microorganisms, viruses, and toxins are examples of pathogens.


Other Word Forms

  • antipathogen noun

Etymology

Origin of pathogen

First recorded in 1940–45; patho- + -gen

Explanation

A pathogen is a tiny living organism, such as a bacterium or virus, that makes people sick. Washing your hands frequently helps you avoid the pathogens that can make you sick. Pathos is the Greek word for disease and -genes means "born of." So, a pathogen is something that causes disease, like a virus like the rhinovirus, which causes the common cold. At summer picnics, people are cautious about keeping certain foods like potato salad in coolers with ice — the eggs in such dishes spoil quickly out in the heat, introducing pathogens that can make people sick.

Keep Reading on Vocabulary.com

Vocabulary lists containing pathogen

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.

The new research, which draws on 40 years of global trade records and pathogen data, attempts to measure the relationship on a larger scale.

From Los Angeles Times • Apr. 13, 2026

Carlson said one of the most striking findings was how strongly time in trade predicted pathogen sharing.

From Los Angeles Times • Apr. 13, 2026

She added that the drugs did not provide effective coverage against a Gram-positive organism, which was the most likely pathogen causing the infection.

From BBC • Mar. 11, 2026

Why do two people exposed to the same pathogen respond so differently?

From Science Daily • Feb. 11, 2026

It does mean, though, that a human population as a whole becomes better protected against the pathogen.

From "Guns, Germs, and Steel: The Fates of Human Societies" by Jared M. Diamond