Lipid (noun)

1. A type of fat or related substance that is insoluble in water.
2. Any of a group of organic compounds that are insoluble in water and include fats, waxes, and certain steroids and other compounds.

Origin:

1884, from german lipide, from greek lipos "fat".

Examples:

1. Lipids are an important source of energy for the body.
2. The diet was high in lipids and led to high cholesterol.
3. Lipids play a key role in cell membrane structure.
4. Lipids are a diverse group of compounds that are important in many biological processes.
5. Lipids are found in all living organisms, both plant and animal, and are a major part of their cell membranes.