microbiology

American  

[mahy-kroh-bahy-ol-uh-jee] / ˌmaɪ kroʊ baɪˈɒl ə dʒi /

noun

1. the branch of biology dealing with the structure, function, uses, and modes of existence of microscopic organisms.

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microbiology British  

/ ˌmaɪkrəʊˌbaɪəˈlɒdʒɪkəl, ˌmaɪkrəʊbaɪˈɒlədʒɪ /

noun

1. the branch of biology involving the study of microorganisms

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microbiology Scientific  

/ mī′krō-bī-ŏl′ə-jē /

1. The scientific study of microorganisms.

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Other Word Forms

• microbiologic adjective
• microbiological adjective
• microbiologically adverb
• microbiologist noun

Etymology

Origin of microbiology

First recorded in 1885–90; micro- + biology

Compare meaning

How does microbiology compare to similar and commonly confused words? Explore the most common comparisons:

• microbiology vs. biology

Explanation

Microbiology is the study of very small things, both living and nonliving. If you're fascinated by looking at tiny organisms through a microscope, you should take a class in microbiology. If your job involves microbiology, you're probably a microbiologist, a scientist who studies microorganisms and other microscopic things. Notice the prefix micro- in all of those words? It means "extremely small," from the Greek root mikros, "small or slight." Add this to biology, "the science of living things," and you get microbiology. This branch of science involves looking closely at fungi, viruses, parasites, bacteria, and other microbes.

Example Sentences

Nineteen-year-old Reyhaneh, who is studying microbiology at the University of Tehran, also holds a photograph of the new supreme leader Mojtaba Khamenei.

From BBC • Apr. 23, 2026

"This is a huge public health crisis in the making," said Covarrubias, who is also an assistant professor of microbiology, immunology and molecular genetics.

From Science Daily • Apr. 16, 2026

“Trained immunity is broad,” says David Topham, a professor of microbiology and immunology at the University of Rochester Medical Center.

From The Wall Street Journal • Dec. 6, 2025

Careers Wales has also told the BBC that life sciences, which include roles within biomedical sciences and microbiology, and the energy industry are seen as the biggest growing sector in Wales.

From BBC • Sep. 30, 2025

Positive results in Martian microbiology were achieved in seven different samplings in two locales on Mars separated by 5,000 kilometers.

From "Cosmos" by Carl Sagan