A steroid is a type of lipid that has four rings of carbon atoms.
Properties that all steroid molecules have in common include:
1. They are all organic compounds.
2. They all have three 6-sided carbon rings and one 5- sided carbon ring.
3. They are insoluble in water.
Steroids are important in biology, chemistry and medicine. Steroids include all the sex hormones, adrenal cortical hormones, bile acids and sterols of vertebrates.
They are used to make anti-inflammatory medicine and also oral contraceptives.