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

Patchen studies how omega-3 fatty acids and vitamin D — another nutrient that fish is rich in — are associated with better lung function and lower risk of chronic obstructive pulmonary disease and emphysema. — Diana Anos, CNN Money, 4 Sep. 2026

While King said more research is needed before any firm recommendations can be made about Alzheimer’s specifically, research shows health benefits of an omega-3-rich diet — especially for women. — Mira Miller, Verywell Health, 3 Sep. 2026

Balsamic Vinaigrette Balsamic vinegar adds sweetness, and olive oil brings a savory flavor with healthy fats like omega-3s. — Lauren O'Connor, HEALTH, 2 Sep. 2026

This looks like prioritizing foods that are high in calcium, vitamin D, and omega-3 fatty acids. — Sarah Madaus, InStyle, 30 Aug. 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