A pharmaceutical is a drug of any kind used for medicinal purposes, like cough syrup or sleeping pills. You may have heard of a pharmacy, which is a place where you can buy medicinal drugs, or a pharmacist, which is a person who prepares those drugs.The definition of pharmaceutical is something related to prescription drugs (Rx) or pharmacies. An example of a pharmaceutical drug is Humira (medicine). A pharmaceutical or pharmacological preparation or product; a drug.A pharmaceutical company, or drug company, is a commercial business licensed to research, develop, market and/or distribute drugs, most commonly in the context of healthcare. These can be generic and/or brand medications. Drug development can be considered a costly and intensive process.