cho·les·ter·ol 
(kə-lĕstə-rôl′, -rōl′)
(kə-lĕstə-rôl′, -rōl′)n.
A white crystalline substance, C27H45OH, that is found in animal tissues and various foods and is important as a constituent of cell membranes and a precursor to steroid hormones. Cholesterol is normally synthesized by the liver and is transported through the bloodstream by different types of lipoproteins, two of which (HDL and LDL) are routinely measured in blood tests.
[cholester(in), former name for cholesterol (CHOLE- + Greek stereos, solid; see ster-1 in the Appendix of Indo-European roots + -IN) + -OL1 (so called because it was first found in gallstones).]