1. (Science: biochemistry)
A pearly, fatlike steroid alcohol, C27H45OH, crystallizing in the form of leaflets or plates from dilute alcohol and found in animal fats and oils, in bile, blood, brain tissue, milk, yolk of egg, myelin sheaths of nerve fibres, the liver, kidneys and adrenal glands. (biology-online.org)
It constitutes a large part of the most frequently occurring type of gallstones and occurs in atheroma of the arteries, in various cysts and in carcinomatous tissue. Most of the bodys cholesterol is synthesised in the liver, but some is absorbed from the diet. It is a precursor of bile acids and is important in the synthesis of steroid hormones. (biology-online.org)
2. (Science: chemical)
A commercial preparation of cholesterol is used as a pharmaceutic aid. (biology-online.org)
A sterol lipid synthesized by the liver and transported in the bloodstream to the membranes of all animal cells; it plays a central role in many biochemical processes and, as a lipoprotein that coats the walls of blood vessels, is associated with cardiovascular disease.
4. A compound of the sterol type found in most body tissues, including the blood and the nerves. Cholesterol and its derivatives are important constituents of cell membranes and precursors of other steroid compounds, but high concentrations in the blood (mainly derived from animal fats in the diet) are thought to promote atherosclerosis. (Google Dictionary)
5. An animal sterol that is normally synthesized by the liver; the most abundant steroid in animal tissues. (wordnetweb.princeton.edu)
Word Origin: from the Greek chole- (bile) and stereos (solid) followed by the chemical suffix -ol for an alcohol.