Generic drug: Any drug that is marketed under its chemical name without any advertisement. These drugs marketed without a brand name are less expensive than brand-name drugs. Such drugs are chemically identical to brand-name drugs and meet the same standard of the FDA (US Food and Drug Administration) for effectiveness, safety, and purity. 'Diazepam' is an e.g of generic name of a sedative. Some companies sold it under its generic name and others sold it as Valium or Vazepam.