polyunsaturated fat

noun

: an unsaturated fat which has more than one double bond in its hydrocarbon chain, that is liquid at room temperature, and that is found especially in fish, walnuts, and many oils (such as sunflower, corn, and soybean oil)

Shellfish are also low in total fat and saturated fat—more important considerations than dietary cholesterol. And they're also reasonably good sources of Omega-3s, the polyunsaturated fats known to lower blood cholesterol, reduce blood clotting, and in animals, prevent heart disease.

—Eileen Behan, American Health

compare monounsaturated fat, saturated fat