Definition of SET THEORY. : a branch of mathematics or of symbolic logic that deals with the nature and relations of sets. â set theoretic adjective. See set theory defined for kids. ADVERTISEMENT.
Broadly, the term lipid is encompasses fats (including saturated, monoglyceride, diglyceride and triglyceride), waxes, sterols, phospholipids in the membranes of cells and fat soluble vitamins. Lipid is a basic term representing a molecule that is fat soluble (vs. water soluble).
Fats are composed of three fatty acids and glycerol. These so called triglycerides can be solid or liquid at room temperature. Those that are solid are classified as fats, while those that are liquid are known as oils.Fatty acids consist of a long chain of carbons with a carboxyl group at one end.il is a type of lipid known as a triglyceride. Solid triglycerides are called fats and liquid triglycerides are called oils. Photo Credit: Credit: Thomas Vogel/E+/Getty Images.