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

Plant foods are an excellent source of omega-3 fats. —Anahad O’Connor, Washington Post, 3 June 2026

Focusing on creating stable mixtures with water-soluble substances such as sugar and oil-soluble ones such omega-3 fatty acids, the team developed a capillary-force system for emulsifying small amounts of water and oil. —New Atlas, 3 June 2026

The omega-3 fatty acid content of these varies widely. —Ayesha Gulzar, Verywell Health, 3 June 2026

Fish like salmon and tuna are rich in protein and contain omega-3 fatty acids, which have positive effects on heart health. —Alyssa Goldberg, USA Today, 2 June 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