Cholesterol: A type of steroid that is essential for the structure and function of cell membranes, and serves as a precursor for other steroids.
Hormones: Chemical substances produced in the body that serve as signaling molecules; some hormones, like testosterone and estrogen, are steroids.
Lipids: A broad group of naturally occurring molecules which includes fats, waxes, sterols (including steroids), fat-soluble vitamins (such as vitamins A, D, E, and K), monoglycerides, diglycerides, triglycerides, and phospholipids