A steroid can mean two different things:
a) an androgen hormone;
b) a synthetic drug that resembles the quality of a steroid hormone.
Steroid hormones begin life as a substance called Trusted sourceCholesterolMedline PlusGo to sourcecholesterol . In a series of chemical reactions, cholesterol undergoes conversion into a series of hormones that fall under the classification of steroids. These chemical changes take place mainly in the adrenal cortex and the sex glands (ovaries and testes).