or ae·ti·ol·o·gy

[ ee-tee-ol-uh-jee ]
/ ˌi tiˈɒl ə dʒi /
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noun, plural e·ti·ol·o·gies.

  1. the study of the causes of diseases.
  2. the cause or origin of a disease.
the study of causation.
any study of causes, causation, or causality, as in philosophy, biology, or physics.



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Origin of etiology

1545–55; <Latin aetiologia<Greek aitiología determining the cause of something, equivalent to aití(a) cause + -o--o- + -logia-logy


e·ti·ol·o·gist, noun
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2021


What does etiology mean?

The etiology of a disease is its cause or origin.

Etiology is also the name for the study of the causes of diseases. It can also refer to the study of the cause of things in other fields, such as philosophy and physics. But it is most commonly used in the context of medicine. In British English, it is spelled aetiology.

Example: The doctors have taken some samples and are working to determine the etiology of the disease.

Where does etiology come from?

The first records of etiology in English come from the mid-1500s. Etiology derives from the Greek aitiología, meaning “determining the cause of something.” This is formed from aitía, “cause,” and –logia, which is the basis of -logy, which indicates the study of something.

In medicine, etiology involves studying the factors that cause a disease. This is done for individual patients to determine how they became sick and to diagnose their illness. But it is also done on a broader scale to determine the origin of diseases. Epidemiologists study how diseases spread throughout large populations and try to detect the source and cause of epidemics.

When a cause of a disease is determined, this is called its etiology. For example, the etiology of cholera is known to be a bacterium that contaminates food and drinking water in places with poor sanitation.

Although etiology is most commonly used in medicine, it can also be used in the context of any field in which the causes of things are studied. An example of etiology in psychology is the study of the causes of mental disorders.

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What are some other forms related to etiology?

  • aetiology (British English spelling)
  • etiological (adjective)
  • etiologically (adverb)
  • etiologist (noun)

What are some words that share a root or word element with etiology?

What are some words that often get used in discussing etiology?


How is etiology used in real life?

Etiology is a formal, technical word that’s primarily used in medicine, but it can be used in other contexts as well.



Try using etiology!

Is etiology used correctly in the following sentence?  

The etiology of a disease isn’t always so simple—sometimes there are multiple factors.

Example sentences from the Web for etiology

British Dictionary definitions for etiology

/ (ˌiːtɪˈɒlədʒɪ) /

noun plural -gies

a variant spelling of aetiology

Derived forms of etiology

etiological (ˌiːtɪəˈlɒdʒɪkəl), adjectiveetiologically, adverbetiologist, noun
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

Medical definitions for etiology



The science and study of the causes or origins of disease.
The cause or origin of a disease or disorder as determined by medical diagnosis.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

Scientific definitions for etiology

[ ē′tē-ŏlə-jē ]

The cause or origin of a disease, condition, or constellation of symptoms or signs, as determined by medical diagnosis or research.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.