Lipids

Lipids are a group of biological macro-molecules that include fats, phospholipids, waxes, and steroids as well as many oils. Because they are hydrophobic (also known as lipophilic; insoluble in water), they constitute a very important component of cell membranes, cell signaling, mechanical support (as adipose tissue), thermal insulation and energy storage (as fats).

This word is sometimes used in advertising to avoid the word "fats", in the (probably accurate) belief that a beauty product's target audience will have failed science at school.