1. 1. A substance used in the diagnosis, treatment, or prevention of a disease or as a component of a medication.
   2. Such a substance as recognized or defined by the U.S. Food, Drug, and Cosmetic Act.
2. A chemical substance, such as a narcotic or hallucinogen, that affects the central nervous system, causing changes in behavior and often addiction.
3. Obsolete. A chemical or dye.

1. To administer a drug to.
2. To poison or mix (food or drink) with a drug.
3. To stupefy or dull with or as if with a drug: drugged with sleep.

[Middle English drogge, from Old French drogue, drug, perhaps from Middle Dutch droge (vate), dry (cases), pl. of drog, dry.]

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.