A lipid is a molecule present in biological organisms. If you have heard the term “lipid” before, you might think that it’s synonymous with “fats”. Fats are, however, triglycerides, a proper subset of lipids. What unites lipids is their solubility in nonpolar solvents.
Fatty acids are an important category of lipids. Soaps used in cleaning and bathing are made from fatty acids. Triglycerides, mentioned already, are another significant category of lipids. Vegetable oils are mixtures of triglycerides. Cholesterol is an instance of another large class of lipids, sterol lipids.