omega-3

adjective

ome·​ga-3 ō-ˈmā-gə-ˈthrē 

-ˈmē-, 

-ˈme- 

: being or composed of polyunsaturated fatty acids that have the final double bond in the hydrocarbon chain between the third and fourth carbon atoms from the end of the molecule opposite that of the carboxyl group and that are found especially in fish, fish oils, green leafy vegetables, and some nuts and vegetable oils compare omega-6

omega-3 noun

Examples of omega-3 in a Sentence

Recent Examples on the Web

Experts recommend baking, pan-searing, steaming, or cold-smoking salmon to preserve the most omega-3s. —Eleesha Lockett, Verywell Health, 20 Feb. 2026

In addition to omega-3s, salmon is an excellent source of protein and vitamins and minerals such as potassium, B12, and selenium. —Jillian Kubala, Health, 19 Feb. 2026

This superstar fish is full of omega-3 fatty acids, which support the structure and function of brain cells and enhance the communication between neurons, explains neurologist Shae Datta, MD, clinical assistant professor in the department of neurology at NYU Grossman Long Island School of Medicine. —Ashley Oerman, SELF, 19 Feb. 2026

What experts say about meal times and health Goodson adds that foods rich in omega-3 fatty acids, including walnuts, salmon and mackerel, also support heart health in other important ways. —Daryl Austin, USA Today, 7 Feb. 2026

Word History

First Known Use

1967, in the meaning defined above

Medical Definition

omega-3

adjective

ome·​ga-3 -ˈthrē 

variants also Omega-3

: being or composed of polyunsaturated fats that have the first double bond in the hydrocarbon chain occurring between the third and fourth carbon atoms from the end of the molecule most distant from the carboxylic acid group and that are found especially in fish, fish oils, green leafy vegetables, and some nuts and seeds

The two main omega-3 fatty acids in fish oil … appear to reduce the risk of dying from sudden cardiac arrest by about 30 percent.

—Nutrition Action Health Letter

compare omega-6

omega-3 noun

also Omega-3

Some plants, such as linseed, naturally produce an omega-3 called alpha-linolenic acid (ALA), and one way to increase the amount of omega-3 in our diet is to eat these plants …

—Andy Coghlan, New Scientist