Illustrated Glossary of Organic Chemistry

Lipid: A hydrophobic (lipophilic) or amphiphilic molecule of biological origin. Lipids are soluble in nonpolar solvents (such as hexane and diethyl ether) and insoluble in polar solvents (such as water).

Lipid Categories and Example Molecules

Stearic acid, a typical fatty acid.   
Glycerol tristearate, a typical triglyceride.

Prostaglandin F (PGF), a typical prostaglandin.   
Cholesterol, a typical steroid.

Alpha-tocopherol, a typical hydrophobic (lipophilic) vitamin.   
Menthol, a typical terpenoid.