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

Chia seeds are high in magnesium, fiber, and omega-3s, which may support sleep and reduce inflammation. — Kathleen Ferraro, Verywell Health, 17 Aug. 2026

Then there are omega-3 fatty acids, which are known to reduce inflammation and support brain health, creating the perfect environment for restful sleep. — Mura Dominko, Martha Stewart, 9 Aug. 2026

Spirulina is a nutrient-dense type of algae rich in protein, omega-3s, B vitamins, iron, copper, and antioxidants. — Christina Manian, Better Homes & Gardens, 6 Aug. 2026

Another possible supplement is omega-3 and omega-6 fatty acids. — Pubsubhub User, Chicago Tribune, 5 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