A polyunsaturate is a kind of fat or oil, usually from plants, that food labels treat as the “better for you” sort, compared with fat from meat, butter, and cream. You almost always meet it in the plural: polyunsaturates. A bottle of sunflower oil, a nutrition panel, a magazine about healthy eating — that is the home of this word. It is a science-and-packaging noun, not a kitchen word your grandmother would use. Though actually, the health story has been argued over for years. The simple school version is: these plant oils are kinder to the heart than animal fats. Real food science is less tidy, and “plant” does not automatically mean “good” if the food is still ultra-processed. Chemically, poly- here means the fat has many “not-full” places in its make-up (the same idea as unsaturated, but more than one of those places). You do not need the chemistry to read a label.

多元不飽和脂肪（作名詞時，多指這類油脂本身）