High-density lipoprotein (HDL) is a type of lipoprotein, a complex molecule composed of lipids (fats) and proteins, that plays a crucial role in the transport of cholesterol in the bloodstream. HDL is often referred to as "good cholesterol" because of its beneficial effects on cardiovascular health.

Unit 2,

Reference: Oxford Concise Colour Medical Dictionary (7th Edition, Kindle Edition) Oxford University Press 2020 ISBN-13: 978-0198836629, p1617