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

Two tablespoons of hemp seeds have just as much protein as two egg whites—along with all nine essential amino acids (a rarity), omega-3, and omega-6. —Margaux Anbouba, Vogue, 25 Mar. 2026

Fish oil — Provides essential omega-3 fatty acids for heart, brain and joint health. —Fred Sassani, Austin American Statesman, 23 Mar. 2026

Walnuts, which are rich in protein and omega-3 fatty acids, have 21% fewer calories than typically believed, according to USDA estimates. —Kaitlin Sullivan, NBC news, 22 Mar. 2026

Vitamin D deficiency has been associated with sleep disorders, Davis said, while omega-3s may play a role in brain function and inflammation, both of which can influence sleep. —Peter Burke, FOXNews.com, 18 Mar. 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