The American Heritage® Dictionary of the English Language, 4th Edition
n. Any of a group of predominantly unsaturated solid alcohols of the steroid group, such as cholesterol and ergosterol, present in the fatty tissues of plants and animals.
n. any member of a class of steroids containing a hydroxyl group in the 3-position of the A-ring; they are found in all animal and plant tissue and play an important role in hormone chemistry
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. any of a group of natural steroid alcohols derived from plants or animals; they are waxy insoluble substances
Word Usage
"Cerebrotendinous Xanthomatosis (CTX) is a rare, autosomal recessive metabolic disorder caused by mutations in a gene called CYP27A1, which produces an enzyme called sterol 27-hydroxylase."