<p><strong>Noun</strong></p><ul><li>(Pharmacology) a chemical substance used in the treatment, cure, prevention, or diagnosis of disease or used to otherwise enhance physical or mental well-being.</li><li>(in federal law) any substance recognized in the official pharmacopoeia or formulary of the nation.</li><li>any substance intended for use in the diagnosis, cure, mitigation, treatment, or prevention of disease in humans or other animals.</li><li>any article, other than food, intended to affect the structure or any function of the body of humans or other animals.</li><li>any substance intended for use as a component of such a drug, but not a device or a part of a device.</li><li>a habit-forming medicinal or illicit substance, especially a narcotic.</li><li>drugs, chemical substances prepared and sold as pharmaceutical items, either by prescription or over the counter.</li><li>personal hygienic items sold in a drugstore, as toothpaste, mouthwash, etc.</li><li>(Obsolete) any ingredient used in chemistry, pharmacy, dyeing, or the like.</li></ul><p><strong>Verb</strong></p><ul><li>(used with object) to administer a medicinal drug to.</li><li>to stupefy or poison with a drug.</li><li>to mix (food or drink) with a drug, especially a stupefying, narcotic, or poisonous drug.</li><li>to administer anything nauseous to.</li></ul><p><strong>Verb Phrase</strong></p><ul><li>(Informal) to take a drug, especially an illegal drug: athletes who drug up in the off-season.</li></ul>