Real Dictionary

dope
countable noun: If someone calls a person a dope, they think that the person is stupid.
uncountable noun: Dope is a drug, usually an illegal drug such as marijuana or cocaine.
uncountable noun: Dope is information which you have been given illegally or secretly.
verb: If someone dopes a person or animal or dopes their food, they put drugs into their food or force them to take drugs.

dope in American English
any thick liquid or pasty substance, or other material, used to lubricate or absorb something
to give dope to; treat with dope
intransitive verb: to take drugs
noun: any thick liquid or pasty preparation, as a lubricant, used in preparing a surface
transitive verb: to affect with dope or drugs

dope in British English
to add impurities to (a semiconductor) in order to produce or modify its properties
adjective: excellent
noun: any of a number of preparations made by dissolving cellulose derivatives in a volatile solvent, applied to fabric in order to improve strength, tautness, etc

dope in Chemical Engineering 1
Dope or a dope is a substance which is added to improve the properties of something.

dope in Chemical Engineering 2
verb: If you dope something, you apply or add a dopant to it.