an unsaturated fatty acid whose carbon chain has more than one double or triple valence bond per molecule; found chiefly in fish and corn and soybean oil and safflower oil

a liquid polyunsaturated fatty acid that occurs in some plant oils; an essential fatty acid

a polyunsaturated fatty acid present in the phospholipids of membranes of the body's cells, and is abundant in the brain, muscles, and liver.

a fatty acid found primarily in vegetable oils.