denoting a class of polyunsaturated fatty acids essential to the human diet, found primarily in oily fish but also in some vegetable oils and leaf vegetables, and beneficial to health by boosting the immune system and combating heart disease and other disorders
[omega denoting the final position in the hydrocarbon chain forming the fatty acid, and -3 indicating that the third carbon-carbon bond from the omega end of the chain is the first double bond from that end]