The American Heritage® Dictionary of the English Language, 4th Edition
n. A colorless unsaturated aliphatic hydrocarbon, C30H50, found especially in human sebum and in the liver oil of sharks, that is an intermediate in the biosynthesis of cholesterol and is used in biochemical research.
n. A triterpene hydrocarbon found in shark liver oil and in human sebum; it plays a role in the biosynthesis of steroids.
Word Usage
"In the United States, squalene is used as an adjuvant only in the anthrax vaccine, but in Europe, squalene has been used for a number of years in several different vaccines."