What does lipid mean?
A lipid is a naturally occurring molecule that belongs to a large biochemical group characterized by poor solubility in water and better solubility in nonpolar substances such as oils. Lipids include fats, oils, waxes, phospholipids, and steroids, although these substances vary greatly in structure and function. Some lipids, including triglycerides, store energy; others, such as phospholipids and cholesterol, are major components of cell membranes and help cells communicate with their surroundings. Steroid lipids also serve as important hormones. In medicine, the term appears in phrases such as “lipid profile” and “lipid panel,” referring to blood tests that assess cholesterol and triglycerides. The word is most common in scientific, nutritional, and health-related contexts. Understanding lipids is useful because they connect everyday ideas such as dietary fat with complex processes involving cell membranes, metabolism, and disease risk.
nounAny of a group of naturally occurring, complex molecules that are poorly soluble in water but soluble in nonpolar solvents. Lipids include fats, oils, waxes, phospholipids, and steroids, and they serve important functions in energy storage, cell membranes, and hormone production.
- A member of a group of naturally occurring molecules, including fats, oils, waxes, phospholipids, and steroids, that are poorly soluble in water and important in energy storage, cell structure, and signaling.
"The cell membrane is largely composed of a double layer of lipid molecules."
"The cell membrane contains a lipid bilayer that separates the cell’s internal and external environments."
"A lipid panel measures the amounts of cholesterol and triglycerides in a patient’s blood."
The plural is commonly used when referring to lipids as a class, especially in discussions of metabolism, nutrition, and medicine.
"Dietary lipids are absorbed in the small intestine and transported through the bloodstream."
A lipid is one of biology’s great non-solubility tricks: many of the molecules that build cell membranes cannot dissolve in water.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does lipid come from?
The word “lipid” comes from Greek lipos, meaning “fat,” combined with a chemical suffix. It entered scientific English in the early twentieth century as terminology for the diverse group of substances now classified as lipids. Related English words include lipophilic, lipolysis, and lipoma, all of which reflect the same Greek root associated with fat.
Related word forms
How lipid is actually used
A formal scientific and medical term, used especially in biochemistry, nutrition, and medicine. In general writing, “fat” may be more familiar, although not every lipid is simply a fat in the everyday sense.