Synonyms

toxin

American

[tok-sin] / ˈtɒk sɪn /

noun

any poison produced by an organism, characterized by antigenicity in certain animals and high molecular weight, and including the bacterial toxins that are the causative agents of tetanus, diphtheria, etc., and such plant and animal toxins as ricin and snake venom.

toxin British

/ ˈtɒksɪn /

noun

any of various poisonous substances produced by microorganisms that stimulate the production of neutralizing substances (antitoxins) in the body See also endotoxin exotoxin
any other poisonous substance of plant or animal origin

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

toxin Scientific

/ tŏk′sĭn /

A poisonous substance, especially one produced by a living organism. Toxins can be products or byproducts of ordinary metabolism, such as lactic acid, and they must be broken down or excreted before building up to dangerous levels. Toxins can facilitate survival, as with snake venom that kills or immobilizes prey, or cyanide produced by some plants as a defense against being eaten. Bacterial toxins can sometimes be neutralized with antitoxins.
Compare antitoxin

Related Words

See poison.

Etymology

Origin of toxin

First recorded in 1885–90; tox(ic) + -in ²

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

The insurer has come under heavy criticism from fire victims over its handling of claims, including complaints of low payout offers, denials for toxin testing and delays in payments for living expenses.

From Los Angeles Times • Mar. 7, 2026

Mice that could not properly process ammonia accumulated higher levels of the toxin.

From Science Daily • Mar. 6, 2026

This weekend, several European countries announced -- after testing his body samples -- that Navalny was poisoned with a rare toxin.

From Barron's • Feb. 15, 2026

Russian dissident Alexei Navalny was almost certainly killed by a poison derived from a rare frog toxin in an Arctic prison colony two years ago, several European governments said Saturday.

From The Wall Street Journal • Feb. 14, 2026

I need to destroy the toxin without watching eyes.

From "The Last Cuentista" by Donna Barba Higuera

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023