germ theory

American  

noun

1. Pathology. the theory that infectious diseases are due to the agency of germs or microorganisms.

2. Biology. biogenesis.

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germ theory British  

noun

1. the theory that all infectious diseases are caused by microorganisms

2. the theory that living organisms develop from other living organisms by the growth and differentiation of germ cells

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Etymology

Origin of germ theory

First recorded in 1870–75

Example Sentences

The author appreciates what a terrific advance modern germ theory represents, but she also recognizes its tendency to generate absurd excesses.

From The Wall Street Journal • Jan. 23, 2026

Dominique Janee: This was before doctors knew much about germ theory of disease.

From Scientific American • Nov. 2, 2023

In other words, it's a bunch of outdated and unscientific ideas from before the germ theory of disease.

From Salon • Nov. 1, 2023

Crowded conditions in the mission dorms, and the lack of understanding of germ theory at the time, led to “incredible mortality,” Hackel says.

From Los Angeles Times • Jun. 28, 2023

Dr. D. W. Bliss was one who thought that germ theory was unproven.

From "Ambushed!" by Gail Jarrow