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).
1 Lipids are fat-like substances found in your blood and body tissues. 2  Your body needs small amounts of lipids to work normally.  A blood test called a complete lipid profile is done.