1. A substance that causes injury, illness, or death, especially by chemical means.
2. Something destructive or fatal.
3. Chemistry A substance that inhibits another substance or a reaction: a catalyst poison.
tr.v. poi·soned, poi·son·ing, poi·sons
1. To kill or harm with poison.
2. To put poison on or into: poisoning arrows; poisoned the drink.
a. To pollute: Noxious fumes poison the air. See Synonyms at contaminate.
b. To have a harmful influence on; corrupt: Jealousy poisoned their friendship.
4. Chemistry & Physics To inhibit (a substance or reaction).
[Middle English, from Old French, from Latin pōtiō, pōtiōn-, drink; see pō(i)- in the Appendix of Indo-European roots.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.