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

In addition to its vitamin D benefits, rainbow trout is also an excellent source of high-quality protein, omega-3 fatty acids, and essential minerals like selenium and potassium. —Kelly Burch, Verywell Health, 28 Nov. 2025

Fatty Fish Fatty fish, including salmon, mackerel, trout, and sardines, are packed with omega-3 fatty acids, which are anti-inflammatory and protect cells. —Jillian Kubala, Health, 25 Nov. 2025

Fatty fish are rich in omega-3 fatty acids, which support both brain function and emotional balance. —Essence, 19 Nov. 2025

Some experts also warn about the potential for nutrient deficiencies — particularly vitamin B12, calcium and omega-3 fatty acids. —Kelly McGreal, FOXNews.com, 17 Nov. 2025

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