Lipids are a diverse group of molecules that play important roles in our bodies, including energy storage, cell membrane structure, and signaling. Synonyms for lipids include fats, oils, triglycerides, phospholipids, cholesterol, and fatty acids. Fats and oils are often used interchangeably with lipids, but may refer specifically to solid or liquid forms of lipids, respectively. Triglycerides are the primary form in which lipids are stored in adipose tissue, while phospholipids are key structural components of cell membranes. Cholesterol is a type of lipid that can be both beneficial and harmful, depending on its level in the blood. Fatty acids are the building blocks of many lipids and are essential for maintaining our health.